Journal of Distilling Science, Winter 2022 by Artisan Spirit Magazine

JOURNAL OF DISTILLING SCIENCE VOLUME 2 NUMBER 1

Winter 2022

SOCIETY OF DISTILLING SCIENTISTS AND TECHNOLOGISTS

AN ARTISAN SPIRIT MEDIA PUBLICATION

SPECIAL THANKS TO OUR SPONSORS Lallemand Biofuels & Distilled Spirits is the industry leader in supplying fermentation products and value-added services to the distilled spirits industry. We specialize in the research, development, production, and marketing of yeast and yeast nutrients as well as a solid belief in eduction of the distilled spirits industry. A vital part of the alcohol production process, fermentation products from Lallemand Biofuels & Distilled Spirits have been designed and selected to create value by tailoring objective solutions to distillery needs.

MGP is known for its mastery in formulating, fermenting, distilling, blending and maturing world-class spirits. The company’s expertise combines art and science to produce premium bourbons, whiskeys, gins and grain neutral spirits serves as the foundation of a lasting legacy. Customers benefit from MGP’s in-depth experience, state-of-the-art capabilities and collaborative approach to developing tailored formulations and meeting precise product requirements. MGP’s team of Master Distillers and Master Blenders, along with the entire production staff at our distilleries in Atchison, KS, and Lawrenceburg, IN, takes great pride in delivering the highest quality results with each and every spirit distilled. For details, visit mgpingredients.com/distilled-spirits.

Rudolph Research Analytical is pleased to be a sponsor of the Journal of Distilling Science and this represents part of our commitment to the Alcohol Production Industry. Rudolph is a 60-year-old manufacturer of high accuracy, high quality laboratory instruments. Rudolph serves the Alcohol production industry with its TTB Approved DDM 2911 PLUS Density Meter and the innovative AlcoTest-RI® system which measures the alcohol content of obscured beverages, without distillation. As an industry partner Rudolph seeks to assist you in the areas of beverage quality, consistency, and compliance so you can provide your customers the highest quality products. Rudolph is always available to help you with quality instruments backed by a team of qualified scientists, engineers, technicians, and experienced staff.

JOURNAL OF DISTILLING SCIENCE

THE OFFICIAL PUBLICATION OF THE SOCIETY OF DISTILLING SCIENTISTS AND TECHNOLOGISTS

JOURNAL OF DISTILLING SCIENCE

THE OFFICIAL PUBLICATION OF THE SOCIETY OF DISTILLING SCIENTISTS AND TECHNOLOGISTS

VOLUME 2

NUMBER 1

Winter 2022

TABLE OF CONTENTS EDITORIAL

ORIGINAL PAPERS

Two and four for 2022-2023

Levels and management of glycosidic nitrile production in North American grown barley varieties

Gary Spedding

Hannah M. Turner, Jamie D. Sherman, Jennifer Lachowiec, Dylan Williams Bachman, and Aaron Macleod

REVIEWS

EDITORIAL

THE JOURNAL OF DISTILLING SCIENCE

Investigating Grain-on Malt Whiskey Production Using Naked Barley

Microfluidics and the Spirits Industry: A Review

Blending Canadian Whisky – A Review

General Guide for Contributors/Authors

James Burns, Calum Holmes, Brigid Meints and Scott Fisk

Tonoy K. Mondal and Stuart J. Williams

Don Livermore

Edition 2021

VOLUME 2 NUMBER 1

Winter 2022

JOURNAL OF DISTILLING SCIENCE

THE OFFICIAL PUBLICATION OF THE SOCIETY OF DISTILLING SCIENTISTS AND TECHNOLOGISTS

VOLUME 2

NUMBER 1

Winter 2022

EDITOR Gary Spedding, Ph.D.

EDITORIAL BOARD Andre R. Alcarde

Seth DeBolt

Jacob Lahne

Darrin L. Smith

Denise R. Anderson

Jeannine Delwiche

Ray Marsili

Nermina Spaho

Robert J. Arnold

Roy D. Desroches

Rob McCaughey

Alex Speers

Luis Ayala

John Edwards

Dean McDonald

Molly Troupe

Jamie Baxter

Christopher J. Findlay

Aaron McLeod

Toshio Ueno

Bradley Berron

Christopher Gerling

Gregory H. Miller

Richard Curtis Bird

Patrick M. Hayes

Conor O’Driscoll

Ana Guadalupe Valenzuela-Zapata

Gordon Burns

Patrick Heist

Matthew Pauley

Derek D. Bussan

Annie Hill

Chris Paumi

Keith R. Cadwallader

Reade Huddleston

Guillaume de Pracomtal

Adam Carmer

Paul Hughes

Andrei Prida

Miguel Cedeno

Frances Jack

Michael Qian

Franklin Chen

John D.E. Jeffery

Elizabeth Liz Rhodes

Thomas S. Collins

Nathan Kreel

Kurt A. Rosentrater

Bowen Wang Akira Wanikawa Stuart Joseph Williams N.A. “Nik” Willoughby Alan Wolstenholme Steve Wright

EDITORIAL POLICIES The Journal of Distilling Science (JDS) is both an online and in-print peer-reviewed journal with an overarching reach for reviews and original research papers dealing with all the science and technology disciplines involved in the production of potable distilled spirits and related alcoholic beverages. Papers will be accepted for review from universities and colleges, research institutes and industrial laboratories, distilleries, raw materials producers, and allied industries supporting the testing and quality control functions of distilling operations. All submissions are sent to three reviewers for assessment with due consideration to confidentiality. To submit your article please email GSpedding@jdsed.com

AN ARTISAN SPIRIT MEDIA PUBLICATION The Journal of Distilling Science (©2023 Artisan Spirit Media) with all rights reserved has been accepted as the official publication of the Society of Distilling Scientists and Technologists (SDST) and is under the editorship of an independent review body appointed and staffed by the founding members of the SDST. Upon formation of the SDST and the full incorporation of the journal into its jurisdiction the editorial committee to be formally approved will assume the greater role of governance over the editorial process. ©2023 ARTISAN SPIRIT MEDIA

PO BOX 31494, SPOKANE, WA 99223

WWW. ARTISANSPIRITMAG.COM/JOURNAL-OF-DISTILLING-SCIENCE

EDITORIAL

Two and four for 2022-2023 First off, apologies for the delay in getting the second issue of the Journal of Distilling Science laid down and into your hands. My tardiness is due, in part, to a move from one state to another and trying to keep up with all the goings on in the brewing and distilling worlds. There are a few other reasons for some delays but my responsibility overall. Excuses over, and hopefully with apologies accepted, let us now drill down into the current issue and the future of distilling knowledge. So, now back to the two and the four. This is the second issue of our new Journal – the key organ for the still forthcoming foundation of the Society of Distilling Scientists and Technologists (the SDST) and its incorporation as an entity, with value to distillers worldwide. Once again, we have four papers to present here, having lost one along the way due to timing issues, and with two more that await approval for issue number three! Raw materials, modern analytical technology, and the little-covered topic of spirits blending form the focus of this issue, with quite the emphasis on whiskies for issue two. Another paper — for a future issue — will also cover some neat new analytical methodologies as applied to whiskies. Herein then, we read about the importance of management of the ethyl carbamate content in whiskies, the history and some specifics of the blending of Canadian whiskies, a look at micro-scale technologies for the quality control analysis and authentication of spirits, and the application of grain-on THE JOURNAL OF DISTILLING SCIENCE

production methods for whiskies with the inherent potential benefit to craft spirits producers. A comment on a repeat of only four papers in the two issues to date. Interesting things are happening in the publishing world. First off, there have only been a handful of papers presented in other more specific brewing-related journals of late. Yet a good few, concerning brewing and distilling, have appeared in the ever-growing market of open-access publications. Some institutions now expect authors to publish largely or only within such platforms. Yet, many of these works are not in dedicated journals for distillers, though some special issues do appear from time to time which cover ground of more interest for our colleagues in our industry. We must become aware of these notable works and that awareness will come from reading great works presented here in the JDS. Unlike many journals we are not part of a major publishing empire and remain beholden to the future members and current foundational members of the SDST. Via communications and social media post responses we already have at least 3000 colleagues interested in reading through the pages of our journal, with its articles fully vetted by three reviewers and without carrying the burden of page charges. Many editors and teams from fully established journals clamor for more author contributions and yet, as noted above, still are not fully dedicated to reaching one key audience. Of course, we are still unknown and so a slow start was expected. I had hoped for issue two and a third issue to be out in 2022, but we are here now and with some material being lined up for the third

VOLUME 2 NUMBER 1

Winter 2022

and subsequent issues. We will attract a key audience with some established author reviews of high quality, and more original works as the word gets out and as the future SDST committee takes over the business of running and promoting the journal. The JDS will become a part of the membership materials for the new society. We can also expect some topic specific issues going forwards but always a mix of good material. While bias is all around us, and we must always try to keep many biases at bay, there are of course a few topics I wish personally to learn more about. However, it is not the place here for me to be wide open in my suggestions, so we present the word map below detailing a few terms that apply to the distilling world and that will hopefully encourage conversations on the need to seek out more knowledge and understanding behind each word and term and how each fits our distilling world. Authors, scientists, distillers, and allied industry professionals: I want you to know that the ears, eyes, and minds of your distilling colleagues need and desire the stimulation of their senses and growth of their understanding of our field from, and via, the knowledge you can impart to us all. In this regard a recent posting of a similar word map with the title heading “Nearly 200 words representing the distilling world” met with some amusement. Several commented, quite rightly, that it would take thousands more words to describe the distilling world. Nuanced terms and keywords are still missing from the map, but not our lexicons. All parties need to come forth and help us build that map and knowledge base in a less scattered way. That is what the JDS stands for, and we hope you 5

will be a part of it, as authors and/ or readers. The JDS is thus to be a worldwide tool for identifying the best practices and options available for potable spirits and higher-alcohol-containing beverages such as sake, for example (see the word map for some detail here). This mission statement illustrates that the audience for such a dedicated journal includes, but is not limited to, current and prospective distillers, chemical engineers, raw materials suppliers, marketers, and academic researchers and students involved in any aspect of distilling-relevant art, history, technologies, and the sciences with the view of producing the highest quality and flavorful potable beverages.

I thank our colleagues Reade Huddleston and Gabe Toth for their excellent scientific and English-language editorial skills and contributions to the final layout. A couple of the authors of the papers now presented for your reading pleasure were grateful to them for pointing out a couple of issues that I and the reviewers had missed. The current authors, and those noted in the first issue, are thanked for taking a chance on such a new publication. We build the base from their foundational works. All our reviewers deserve full credit for the work they did to help us bring substantial works forth in the still early days of this mission. I look forward to giving them more good material – and

a lot of it in the coming months and years. At this point I finish by introducing Dr. Harmonie Bettenhausen from Hartwick College. Dr. Bettenhausen had offered to get more involved with the editorial work for the journal and I look forward to her involvement and to the continued growth of our journal. I know I speak for us both by promoting our desire to seek your contributions to the next issues of the journal and beyond. Bring them on! Gary Spedding (Appointed as the initial lead science editor by the organizing body of the forthcoming Society of Distilling Scientists and Technologists)

THE JOURNAL OF DISTILLING SCIENCE

12/20/2022

VOLUME 2 NUMBER 1

Winter 2022

Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pi Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Cachaça Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose So Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring Barrels Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Mashing Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Coriander Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fix Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terpenes Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit Wood Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Ba Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Di Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Warehousing Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palo Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Aperitif Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Shikomi Joy White Kobo Kokuto Koshu Kuri Kuro Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQ LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bottling Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmosp Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sodawari Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spo Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfiltered Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Co Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length Acids Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Alambic Alembic Huichol Ancestral Vinasses Abocado Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Mad Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potatorum Palenque Palm Tepache Taverna Vinatero Horno Fructano Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ACS ASBC Genshu ADI ASBC MBAA OIV ASEV IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable H Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU S Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amb Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Q Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Ca Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose Solvent Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring Barrels Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Ma Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Coriander Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fixatives Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terpenes Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit W Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Dioxide Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Wareho Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palomino Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Ap Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Shikomi Joy White Kobo Kokuto Koshu Kuri Kuro Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQUOR LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bo Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmospheric Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sod Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spoilage Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfil Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Corazon Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Alambic Alembic Huichol Ancestral Vinasses Abocado Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Madurado Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potatorum Palenque Palm Tepache Taverna Vinatero Horno Fru Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ACS ASBC Genshu ADI ASBC MBAA OIV ASEV IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable Hybrid Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH IND JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU SOJU Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel M Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Ma Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toa Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Cachaça Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol W Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose Solvent Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring Barrels Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Mashing Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Cori Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fixatives Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terpenes Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit Wood Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Pa Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pec Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Dioxide Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Warehousing Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream D Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palomino Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Aperitif Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Shikomi Joy White Kobo Kokuto Koshu Kuri Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQUOR LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bottling Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckw Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmospheric Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sodawari Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Pr Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spoilage Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfiltered Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi S Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Corazon Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length Acids Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Alambic Alembic Huichol Ancestral Vinasses Abo Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Madurado Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potatorum Palenque Palm Tepache Taverna Vinatero Horno Fructano Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ACS ASBC Genshu ADI ASBC MBAA OIV A IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable Hybrid Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU SOJU Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Ta Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mas Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram Worm Tub Blended Vatted Va Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Cachaça Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction 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Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descri Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Dioxide Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Warehousing Rickhouse Cooper COOPER Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palomino Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar 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Physics Caramel Coloring Demerara Fermentable Hybrid Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Art TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU SOJU Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Lea Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Ca Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal 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Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share V Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Wh SENSORY QC QA Quality Mezcal Agave Tequila Sotol Cachaça Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose Solvent Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring B Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Mashing Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Coriander Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fixatives Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terp Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit Wood Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bac White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic 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Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmospheric Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Ko Newmake Shikumi Swan Neck Mizuwari Oyuwari Sodawari Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spoilage Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji SweetPotato Basket Type Still Undiluted Proofed Unfiltered Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Corazon Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phen Butyrate Caproic Caprylic Medium Chain Length Acids Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Alambic Alembic Huichol Ancestral Vinasses Abocado Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Madurado Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potat Palenque Palm Tepache Taverna Vinatero Horno Fructano Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ACS ASBC Genshu ADI ASBC MBAA OIV ASEV IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable Hybrid Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipi WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU SOJU Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Auto Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Mult Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogs Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram 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Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy G Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Dioxide Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Warehousing Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabez Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palomino Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Aperitif Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Sh Joy White Kobo Kokuto Koshu Kuri Kuro Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQUOR LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bottling Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro K Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmospheric Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sodawari Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Sat Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spoilage Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfiltered Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectific JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Corazon Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length Acids Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Ala Alembic Huichol Ancestral Vinasses Abocado Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Madurado Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potatorum Palenque Palm Tepache Taverna Vinatero Horno Fructano Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ASBC Genshu ADI ASBC MBAA OIV ASEV IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable Hybrid Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas S Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU SOJU Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygen Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amburana Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Quaich Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pi Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Cachaça Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose So Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring Barrels Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Mashing Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Coriander Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fix Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terpenes Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit Wood Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Ba Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Haze Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Di Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Warehousing Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palo Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Aperitif Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Shikomi Joy White Kobo Kokuto Koshu Kuri Kuro Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQ LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bottling Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmosp Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sodawari Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spo Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfiltered Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Co Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length Acids Infographics Mapping Authentication Smoked Charcoal Heriot Watt DMS Masonry Pit NOM Pechuga Alambic Alembic Huichol Ancestral Vinasses Abocado Destilado Mazo Ordinario Maguey Mezcaleros Metl Furfural Acetylfuran Ensamble Mad Tequileros Vinatero Gusano Agavina Asparagacea Agavoideae Angustifolia Potatorum Palenque Palm Tepache Taverna Vinatero Horno Fructano Fructans Inulin Canoa Campana Tequilana Weber varAzul Penca Raicilleros Rectificación Tahona Píñas ACS ASBC Genshu ADI ASBC MBAA OIV ASEV IBD Engineering Theoretical Math Physics Caramel Coloring Demerara Fermentable H Multi-column Solera Navy Tanning Yeast Sugar Cane BRAZILIAN CARIBBEAN Caipirinha WHISKY BOURBON RYE SCOTCH IRISH INDIAN JAPANESE Slàinte Artisanal TeXiang Medical Slivovitz RUM SAKE Rhum Agricole Christmas Spices Carbamate Appellation d’Origine Controlee AOC Cloves Cinnamon Vanilla Lactone Coconut Celery SHOCHU AWAMORI BAIJIU S Mescal MEZCAL Piña Penca Jimador Coa Quiote Mixto Cristalino bagazo Musto Horno Autoclave Diffuser Tahoma Mills Mill Roller Grist Aguamiel Mosto Top Note Middle Leathery Heads Hearts Tails Feints Base Acids Bases Microoxygenation Microoxidation Tyloses Lignin Lignans Hemicellulose Tannins Quinones Acetals Hypothesis Statistical Theory Null Hordeum vulgare Glutinous Amb Rose Hydrophobic Hydrophilic Solubility Volatiles Fixatives Tenacity Molecular Clusters Multishot Singleshot Oryza sativa Wheat Starch Glucose Maltose Fructose Cachón: Clasificación Picón Enólogo Saccharomyces cerevisiae LAB Odor Perception Orthonasal Retronasal Malted Malt Barley Mash Tun Angels Share Vapor Pressure Vaporization Partition Coefficient Partial Spirit-safe Q Lyne Enthalpy, Entropy Gibbs Free Energy Function Peat PPM PPB Pagoda Roof Sorghum Hogshead Nosing Nasal Thief Firkin Alligator Char Toasting Newmake Wort Degrees Celsius Contraction Proof ABV ABWt Strength Finishing Pipette Saké Poitín Poteen Dram Worm Tub Blended Vatted Valnich Cask Whiskey Whiskies SENSORY QC QA Quality Mezcal Agave Tequila Sotol Ca Sake Shochu Science Technology Peat Pot Column Still Distillation Fermentation Brandy Cognac Grappa Pisco eaudeVie Thermodynamics Ethanol Water Contraction Viscosity Chemistry Kinetics Enzymology Fructans Glucose Maltose Solvent Water Forestry Cooperage Seasoning Fungi Mycology Toasting Charring Barrels Hydrogen Bonding Yeast Nutrients Lactic Acid Bacteria Liquid Ma Volume Reduction Saccharification Moonshine Volatiles Botanicals Kome Mugi Soba Imo Kokuto Awamori Baijiu Qu Gin Jenever Genever Juniper Coriander Angelica Maturation Blending Proofing Packaging Stability Liqueurs Cocktails Fixatives Multishot Oxygen Microoxygenation Oxidation Lignin Hemicellulose Terpenes Vanillin Tannin Copper Ions Acids Bases Acetic Maillard Spirit W Catalytic Engine Biology Agronomy Valorization Microbiology Biochemistry Barley Corn Rice Sorghum Potatoes Molasses Sugar Cane Koji Multiple Parallel Solid State Daqu Nuruk Mashing LightRum Aquavit Anise Ouzo Pastis Tsipouro Bacteria Calcium Stress Threshold Indian Japanese Terroir Provenance Raicilla Sisal Bacanora White Rested Anejo SolidState Maceration Extraction Chill Finings Off-flavors Taints Descriptors Orthonasal Retronasal Camphoraceous Balsamic Trigeminal Spicy Grains Herbs Fruits Vegetables Worms Pechuga Hydrogen Bonding Acrolein Ethanol Congeners Cans Bottles Carbonation Carbon Dioxide Charcoal Strecker Sulfur Lightstruck Skunky Olfactory Azeotrope Plates Lynearm Alembic Huichol Dasylirion Coffey Continuous Diacetyl Wareho VOLUME 2 NUMBER 1 Rickhouse Cooper COOPERAGE Coopering Wah Back Bere Age Ruby Reserve Barro Bota Cabezuelas Viticulturist Cachon Cavadores Cream Dulce Espirraque Madre Manzanilla Moscatel Vinification Tawny Treading Fino Flor Palomino Pisadores Retundir Orojus Armagnac Applejack Pisco Grappa BrandydeJerez Kirschwasser Calvados Amoroso Oloroso Arroba Abra Acomodar Albariza Ap Brand Himbeer Apfel Kirsche Williams Pear Poivre Aspergillus oryzae Amami Umami Hinohikari Shikomi Joy White Kobo Kokuto Koshu Kuri Kuro Mizuwari Mugi Roka Shuzo Soba Toji Waramizu FuyuXiang Shaojiu CHINESE LIQUOR LIQUEUR ChiXiang JiangXiang FengXiang Sesame ZhimaXiang YaoXiang LaobiaganXiang NongXiang QingXiang Xiao Qu Sauce Rice Phoenix Bo Carbonation VO VS VSOP Napoleon XO Varietal Vintage Horsd’Age Sulfury Sulfitic Sulfidic Kuro Kojikin Multiple-Parallel-Fermentation Buckwheat Koji Black Yellow Moromi Floral Jar Earthenware Mineralo Spores Honkaku Atmospheric Fusel Fuselly Diastatic Enzyme Oily Distillate Mold Lightstruck Devilscut Cru Kusu Koshiki Newmake Shikumi Swan Neck Mizuwari Oyuwari Sod Maceration Shikumi Mizu Kome Rice 2-Row 6-Row Kobo Seibaku Saccharification Sake Lees Cake Satsuma Imo Vacuum Water Alkalinity Lincoln Process Kojikin Polishing Triangle Tetrad Descriptive Free-choice Profiling Receiving Tank Spoilage Microbial Wild Yeast Diastaticus Torulaspora Zygosaccharomyces Steaming Whitekoji Shiro SweetPotato Basket Type Still Undiluted Proofed Unfil Satsuma Imo Receiving Roasted Pungent Furans Hydroxymethylfurfural Methanol Pectins Toji Rectification JDS ACSA MBAA ADI SWRI BRi SDST Flavor Wheel Beam Institute FU Cabezas Buffalo Trace Heaven Hill Woodford Reserve Corazon Colas Resinous Woody Rancid Varnish Acetone Acetaldehyde Ethyl acetate Phenethyl Butyrate Caproic Caprylic Medium Chain Length

Hypothesis

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Math Theoretical Volatiles Aguamiel

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Tannins

Statistical

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Multishot Whiskies

Char Alligator

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Cocktails Science Enzymology Technology

JOURNAL ABWt Sensory DISTILLING Tub Solubility Worm SCIENCE Lactone

Blended

Angels Share Chill Malted

Juniper

Theory BOURBON Cachón Saccharification Liquid Vanillin Carbamate Middle Mashing Chemistry Catalytic Volatiles Packaging Entropy Orthonasal Grappa Perception Blending Fixatives Lyne Reduction Imo RYE Oxygen Terpenes Horno Coefficient Microoxygenation TeXiang Toasting Celsius Saccharomyces cerevisiae Qu Maltose Partition Herbs Multishot Clusters Fixatives Yeast Molecular Fructans Glucose Maillard Function Engine Mycology Proofing Pot Hydrophobic Jimador Mash Tun Copper Nasal Angelica Genshu Biology Null Barrels Saké Quiote MBAA Picón Christmas Spices Stability PPM Tanning Starch Fermentable Physics Kome Taints Grist Lignans Retronasal Engineering Singleshot Multi-column Cans Tannin Rhum Proof ASBC PPB Spicy CARIBBEAN Slivovitz Kokuto OF Mescal Genever

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Hydrogen

Winter 2022

Botanicals

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ASBC Medical Hydrophilic Quaich Artisanal

Baijiu

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Caipirinha

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Sugar Cane

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Quality Microbiology Still

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BAIJIU Haze Pipette Brandy QA Mills Acids Vanilla Cask SCOTCH Mill Roller Contraction Ions Cinnamon Agricole Awamori Rose Whiskey Gin Penca Mosto Threshold Extraction Calcium Malt Barley Viscosity Pechuga Bottles Thermodynamics MEZCAL JAPANESE Forestry Partial Hydrogen Vatted Piña Solid Hemicellulose Tails Glucose Liqueurs Coa State Barley Coconut Fructose Finishing Koji Sotol Caramel Coloring Glutinous Strength OIV Yeast LAB Peat Shochu BRAZILIAN Oryza sativa Bacteria Navy Agronomy Vegetables IBD ADI Amburana Rested Jenever Aquavit Dram INDIAN Biochemistry Seasoning Cognac Distillation Enólogo Raicilla Tequila Dioxide Microoxygenation Agave Pressure Clasificación Cooperage Contraction Wort QC Ethanol Enthalpy Cristalino bagazo Daqu ABV IRISH Bases Anise Cachaça Valorization Maceration Water Lignin Bacanora Balsamic Coriander Soba Rice Maturation Fermentation Bonding Wheat Pisco Potatoes Molasses Mixto Quinones Hordeum vulgare Newmake Provenance Ouzo Poteen Appellation d’Origine Controlee Off-flavors Tahoma Volume Terroir Vaporization

ORIGINAL PAPER

Levels and management of glycosidic nitrile production in North American grown barley varieties Hannah M. Turner1*, Jamie D. Sherman1, Jennifer Lachowiec1, Dylan Williams Bachman2, and Aaron Macleod2 1 Montana State University, Barley, Malt & Brewing Quality Lab, Bozeman, MT 2 Hartwick College Center for Craft Food & Beverage, Oneonta, NY

KEYWORDS Glycosidic Nitrile Ethyl Carbamate malt barley distilling

Glycosidic nitrile (GN) from malted barley has been identified as the primary precursor of ethyl carbamate (urethane) in new-make whiskey. A specific GN, epiheterodendrin (EPH), is responsible. EPH is a type of cyanogenic glycoside, forming toxic hydrogen cyanide in the pathway leading to ethyl carbamate (EC). The presence of EC, a known carcinogen in many fermented foods, is regulated to varying degrees. For whiskey, the Canadian government has mandated a 150 ppb limit, while the US has a voluntary limit of 125 ppb. In Europe, standards call for newly released distilling barleys to be of the non-GN type. North American breeders are just beginning to select for non-GN and options are likely a decade away. This work considers GN levels of common North American varieties and evaluates malting regime variations, including steep out moisture (40 percent and 45 percent), length of germination (two, four, and six days), and temperature (14 °C, 15 °C and 16 °C) to determine impacts on GN. General standards hold that low producers fall under 0.5 g/tonne GN while high producers sit over 1.5 g/tonne. Varieties tested here averaged 0.20 – 1.52 g/tonne across treatments. As expected, management to minimize acrospire growth mitigated GN while all three process variations had significant impacts: ranges being 0.70 – 1.38 g/tonne (germination time), 0.83 – 1.09 g/tonne (temperature) and 0.56 – 0.96 g/tonne (steep out moisture). While this work does not provide a long-term solution, management is a tool while breeding programs develop North Americana non-GN varieties.

INTRODUCTION Glycosidic nitrile develops in the living tissues of barley including leaves and shoots (rootlets not included). Cyanogenic glycosides such as GN act as a defense mechanism for plants against pathogens and herbivores [1, 2]. However, in the distilling process GN is enzymatically converted to cyanide which then becomes EC in the presence of copper and ethanol, with heat promoting the conversion. It is known that GN production is under genetic control [3] and markers have been developed to assist breeding programs in selection for the trait, specifically selecting for EPH-null genotypes [4]. These markers were proprietary until recently when made available for purchase through Heriot-Watt University. Access to this tool is an important boon for North American breeders. Although the malting process typically aims to minimize growth of acrospires (barley’s initial shoot), GN 8

levels are greatly increased in malted barley as compared to unmalted grain, and extended germination times and excessive acrospire growth are associated with high levels of EC precursors [5]. With North American EPH-null varieties years away from regular production and the potential for greater regulation of EC at any time, maltsters and distillers must work together to manage its production in malt spirits. There are two points at which management practices can be employed: pre-distillation considerations of the ingredients to be used, and in the methods used for distillation. Here we discuss best practices from both aspects for management of ethyl carbamate in malted grain spirits. In 1990 the United Distillers International Research Centre released three articles detailing early understanding of the production of glycosidic nitrile in malting barley, identifying measurable cyanide (MC)

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which later reacts with ethanol in the presence of copper to produce EC. Table 1 provides clarifying definitions for the various compounds to consider in this discussion. As GN is a product of plant leaf and shoot tissues it makes sense that levels are below the detectable limit in unmalted grain, but increase readily with malt processing as this inevitably allows the growth of the grains initial shoot, or acrospire. Various publications reference measurement of potential for EC production via quantification of MC after addition of yeast or β-glucosidase. MC is a measure of total cyanide including hydrogen cyanide, copper cyanide complexes, and cyanohydrins. Other reservoirs of measurable cyanide include lactonitrile, free cyanate, and thiocyanate [10]. Cook, et al. [5] methodically characterized MC levels in germinating barley to be a specific component of acrospires and indicated the impact of variety along with a negative correlation with corn size. The effect of corn size makes sense as the ratio of acrospire to other grain tissues would decrease with larger corns. That work also found positive correlations with grain moisture content during germination, germination temperatures, air ventilation, germination time and usage of gibberellic acid. Crop year and growing location were indicated to not have an impact on barley GN levels. Malted barley plays a key role in the production of malt whiskey, where it is the primary ingredient, but also in other distilled TABLE 1 Definitions of common terms in the discussion of GN and EC. spirits utilizing malted barley for enzymatic conversion of starches from adjunct grains COMPOUND DESCRIPTION such as corn, wheat, rye and more. DistillTerm used to describe a chemical compound that ers working exclusively with unmalted cecontains a cyanide functional group covalently Glycosidic real grains and exogenous enzymes bypass bonded to a sugar. Naturally found in many plants, Nitrile(GN) the potential for production of EC due to the cyanogenic aspects act in plant defense mechaGN. However, with the rise of the craft spirnisms against pathogens and herbivores. it industry, emergence of American single A class of secondary metabolites found in plants malt whiskeys, and distillers incorporating Cyanogenic that release hydrogen cyanide gas when exposed to unique ingredients, it is important to note Glycosides the hydrolyzing enzymes β-glycosidases [11]. there are other potential sources of GN aside A specific glycosidic nitrile (GN) and type of cyanofrom malted barley. For example, sorghum, genic glycoside synthesized in barley seeds during sugar cane and stone fruits contribute to ingermination. Culprit precursor for cyanide produccreased risk for EC production [12, 13]. Epiheterodendrin tion in grain distillation, currently indicated as the EPH is considered the only cyanide releas(EPH) primary cause of EC in malt-based spirits. Markers ing source present in barley [14], making its have been developed to select for varieties which are presence in varieties of great importance to inactive for the EPH gene. the distilling process. It is arguably the main Early investigations of EC formation generally meaconcern for whiskey distillers when considMeasurable sured precursors as measurable cyanide. Modern ering EC production, however other potenCyanide (MC) understanding has specifically identified EPH as the tial precursory sources have been proposed. source. In wine, management of nitrogen and FeII,III fertility levels has been indicated as an imAKA urethane, a known carcinogen contained in Ethyl Carbamate portant EC control point, however these many fermented foods. Its presence in consumer (EC) compounds do not distill and therefore products has become regulated in various countries.

as involved in EC accumulation in whiskey [5-7]. Precisely, Epiheterodendrin (EPH), a glycosidic nitrile, has since been named as the culprit precursor for cyanide production in grain distillation and it is currently indicated as the primary cause of EC in malt-based spirits. GN is a type of cyanogenic glycoside, compounds having the ability to release noxious hydrogen cyanide which is highly toxic to most living organisms. This toxicity is due to hydrogen cyanides’ ability to inhibit the electron transport system by binding cytochromes [8] and arresting metabolic activities. This toxicity has been found to offer plants a chemical defense mechanism whereby the chewing action from insects allows hydrolyzation of the glycoside by β-glucosidase. Under normal conditions β-glucosidase is spatially separated by plant tissues [9]. Interestingly, and unlike other cyanogenic plants, no specific β-glucosidase for this reaction is present in barley leaf tissues, meaning the function is not operational [2]. Specific to the distilling process, β-glucosidase has been indicated as present in barley grain endosperms; however, the enzyme is rendered inactive at normal mashing temperatures (145 °F/63 °C) [5], preventing action during fermentation. Hydrolysis is completed when yeast for fermentation is added. β-glucosidase introduced from yeast leads to hydrogen cyanide production

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FIGURE 1 Control points for GN production and EC formation throughout the whiskey process.

Figure adapted from Elmaghraby [20].

are not of issue for distilled spirits [10]. Riffkin, et al. [15] demonstrated that one source of the cyanate precursor is the oxidation of amino acids by sodium hypochlorite, a strong oxidizer which has been used as a cleaning agent in distilleries and as a biocide/fungicide in the treatment of distillery grains. Riffkin, Wilson and Bringhurst [16] also distilled bovine serum albumin in a laboratory copper alembic still and showed that ethyl carbamate was detected in the distillate at 38 ppb (0.04 g/tonne) after 72 hours elapsed time, demonstrating that amino acids from diverse sources could provide a source of cyanide precursors, albeit in seemingly very low proportions compared to MC. Amino acid sources in malt increase to a point as the malting process progresses. Total protein is modified to soluble protein and free amino nitrogen (FAN). Conscious maltsters will

work to manage degree of modification which will stabilize both acrospire growth and FAN production. Additionally, commercial fermentations typically utilize the majority of wort FAN prior to distillation as FAN is a primary source of yeast nutrition and FAN remaining in beer has been linked to off-flavor production [17]. These alternative sources for EC production point to the need for each distiller to intimately understand their raw material as well as cleaning and production practices. Figure 1 details the process of whiskey production from malting through maturation, highlighting key points for EC production control, including raw ingredient selection and copper placement within the distillation process. Careful raw material selections combined with best distilling practices will execute the greatest control of EC.

TABLE 2 Malting barley varieties commercially grown in North America and assessed in this study’s initial malt survey. VARIETY

HEAD TYPE

PLANTING TYPE

BREEDER

AAC Synergy AC Metcalfe Newdale CDC Copeland Conlon Pinnacle LCS Genie LCS Odyssey Full Pint Endeavor LCS Calypso LCS Violetta Thoroughbred

Two Two Two Two Two Two Two Two Two Two Two Two Six

Spring Spring Spring Spring Spring Spring Spring Spring Spring Winter Winter Winter Winter

Agriculture & Agrifood Canada Agriculture & Agrifood Canada Agriculture & Agrifood Canada University of Saskatchewan North Dakota State University North Dakota State University Limagrain Cereal Seeds Limagrain Cereal Seeds Oregon State University USDA – ARS (Aberdeen, ID) Limagrain Cereal Seeds Limagrain Cereal Seeds Virginia Tech

MATERIALS AND METHODS SURVEY OF GN LEVELS IN COMMONLY GROWN NORTH AMERICAN VARIETIES

A study was conducted consisting of seventy-eight malt samples representing different varieties of barley collected from commercial and craft malthouses in North America. Malts were assessed for GN content as described later in this document. Varieties considered are listed in Table 2. MANAGEMENT OF GN

Micro malting trials were conducted on both low and high GN producing varieties as well as an unknown modern release (Buzz) from the MSU breeding program to investigate the effect of germination, moisture content, temperature and time on the level of GN in the resulting

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malts, as well as potential interactive effects. Barley grown in trials at the Montana State University Post Farm in Bozeman Montana in 2018 was sourced for five common malting varieties: Hockett, Metcalfe, Odyssey, Buzz and Synergy. Barley was malted in three replicates for each variety in each treatment according to a standard MSU malting protocol with Custom Laboratory Products (Milton Keynes, U.K.) steep/germ tanks and a kiln. Samples of barley (120 g), plumped over a 6/64” sieve, were loaded into round steeping cages (19.05 cm diam. x 12.7 cm tall), with four quadrants. Each steep tank accommodated four cages, allowing 16 samples to be malted simultaneously. Typically target steep out moisture is 45 percent. A control line (Genie) was included in every run to ensure uniformity of malting between runs. The basic regime consisted of a 48-hour steep, in which grain was continually maintained at 15 °C and underwent a multi-steep program with a steep/rest pattern of 10-hour steep, 18-hour rest, six-hour steep, 10-hour rest, and four-hour steep, with an average target moisture of 45 percent. Germination consisted of 96 hours at a constant 15 °C. Throughout steeping and germination, humidity was maintained at greater than 98 percent and agitation consisted of five minutes of cage turning at 0.61 RPM in every 30-minute period. Aeration with moist air through the grain occurred for one out of every 10 minutes. After germination, samples were kilned via forced air in the CLP kiln over a 24-hour period consisting of 12 hours at 60 °C, six hours at 65 °C, two hours at 75 °C, and three hours at 85 °C. Upon completion, samples contained on average 4.0 percent moisture and were manually

Turner et al.

de-culmed. Alterations to the program were made to assess regime change effects on glycosidic nitrile. Variations included steep out moisture at both 40 percent and 45 percent, time in germination (two days, four days, and six days), and malting temperature (14 °C, 15 °C, 16 °C). Due to limited time and resources a fully factorial evaluation of all malt regime combinations was not possible. GLYCOSIDIC NITRILE ANALYSIS

GN levels in malt were measured following Method 4.21 of the European Brewing Convention. Briefly, malted barley samples were ground in a Buhler disk mill to pass through a 1.5mm screen. The grist was suspended in a buffered solution containing beta-glucosidase and incubated at 60 °C for one hour with intermittent stirring. The resulting mash was distilled, the distillate was assayed for cyanide by reaction with Chloramine-T, and absorbance was measured with a spectrophotometer at 590 nm. A standard curve of KCN was prepared and used to convert absorbance to g/tonne of GN. STATISTICAL ANALYSIS

Three main factors were tested for impact on GN levels: steep-out moisture, time in germination, and malting temperature. Because the experimental design was not full factorial, the impact of each factor was determined in a specific subset of data to reduce unintended variability. Examining the impact of germination time was examined in 15 °C and 45 percent steep-out moisture. The impact of temperature was examined for four days of germination and 45 percent steep-out moisture. The impact of varied steep out moisture was examined for four days of germination and 15 °C. Response variables FIGURE 2 Levels of GN in North American commercial and craft malts surveyed. GN per tonne, β-glucans, and soluble protein were each examined using univariate linear models. Three models were produced: steep out moisture by variety, time in germination by variety, and temperature by variety. Model assumptions were examined using diagnostics plots. Significant interactions were observed for all models. Post-hoc means comparisons were made based on these models using Tukey’s tests with p = 0.05.

RESULTS

Seventy eight malt samples representing different varieties of barley were collected from commercial and craft malthouses across North America and evaluated for GN levels. Here boxplots represent the range for the 11 commonly grown varieties represented in the survey. The green line at 0.5g/tonne represents the threshold under which lines would be considered non-GN producing, while the orange line at 1.5g/tonne represents the threshold at which lines falling above would be considered high GN producers. THE JOURNAL OF DISTILLING SCIENCE

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GN PRODUCTION LEVELS OF BARLEY VARIETIES CURRENTLY GROWN IN NORTH AMERICA

Levels of GN have been successfully lowered in UK barley varieties through selective breeding, however little is known about the levels in 11

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North American barley varieties. A goal of this work was to establish baseline levels of GN for barley varieties commonly grown in North America. Barley varieties are typically categorized according to their propensity to produce GN with three categories established: EPH-null genotype: <0.5g/tonne, Low-producer: 0.5-1.5 g/tonne, High-Producer: >1.5g/tonne. Table 2 lists the cultivars evaluated. The collection includes spring, winter, two and six row varietals that are commonly used in commercial and craft malt operations across the country. Figure 2 displays the measured GN for each variety, determined as described in the methods.

points well below the accepted threshold of 0.5 g/tonne and resulting in an average rate of 0.18 g/tonne GN.

MANAGEMENT OF GN CONTENT OF NA VARIETIES DURING MALTING

SSteep out moisture, time in germination and germination temperature were tested to determine impact on GN production in a selection of two-row malting barleys, Figure 3. Time in germination allows metabolic processes to progress allowing acrospire growth, which correlates with increases in GN. This effect can be seen with GN-producing cultivars having increasing GN values with progressive days of germination. Increasing germination time from two days to six days increased GN per tonne for Hockett, Metcalfe, and Synergy (p < 0.05, Tukey’s test). The increase from two days to four days was sufficient to detect an increase in Buzz (p < 0.05, Tukey’s test). However, Synergy, Metcalfe, Buzz and Hockett are all over the threshold limit of 0.5 g/ tonne with only two days of germination (treatment averages being 1.19, 1.05 and 1.43 g/tonne respectively), while Hockett is the least offensive, having an average rate of 0.71 g/tonne. The only variety maintaining acceptable levels and not impacted by germination time is Odyssey, which due to lack of GN production remains stable throughout with all

IMPACT OF VARIED MALTING PARAMETERS ON GLYCOSIDIC NITRILE LEVELS:

Metabolic processes are favored to a point with increased temperature. Increases of temperature were also found to have negative impacts with elevated levels of GN production (Figure 3). An increase in temperature from 14 °C to 16 °C increased GN per tonne in Synergy, Odyssey and Metcalfe (p < 0.05, Tukey’s test). Varietal rankings remain as compared to time in germination, with Odyssey maintaining low levels (average = 0.21 g/tonne), Hockett having mid-range GN levels (average = 0.68 g/tonne), and Synergy, Metcalfe and Buzz again producing moderate to high levels of the EC precursor (averages = 1.14, 1.01, and 1.76 g/tonne GN respectively). Buzz in particular shows signs of high GN production with all three treatments above the 1.50 g/tonne threshold. Steep-out moisture is a critical control parameter during the malting process. Sufficient hydration is necessary for barley embryo health and is required for moisture dispersion across the endosperm, allowing hydrolytic movement and action of enzymes central to the modification process. Depending on the desired malt style, maltsters target 42 to 45 percent moisture at steep-out. In the interest of elucidating control for GN with this metric here we tested 40 percent and 45 percent steep-out moistures. Higher steep-out moisture was found to contribute to higher GN levels in the malt. Elevated moistures did not impact Odyssey (Figure 3). The remaining varieties have levels above the EPH-null genotype threshold even at 40 percent steep-out moisture and show significant GN increase at 45 percent (p < 0.05, Tukey’s test), although Hockett’s increase was marginal.

FIGURE 3 Germination time, temperature, and steep out moisture impact on Glycosidic Nitrile levels.

Impact of varied malting parameters on glycosidic nitrile levels. Time references time spent in germination, temperature variations were applied during germination and moisture percent references grain moisture at steep out. Error bars indicate the standard error of the mean (n = 3). 12

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Buzz was impacted to FIGURE 4 Soluble Protein & β-glucan levels of selected barley varieties under median trial malting conditions. the greatest extent, with the 45 percent moisture treatment being the only of the group to surpass the 1.50 g/tonne threshold at 1.77 g/tonne GN. To provide context with respect to the level of modification, β-glucan and soluble protein levels for selected treatments are provided, Figure 4. Samples measured for this reference point all had 45 percent moisIllustration of grain modification for selected varieties under standard conditions of 45% moisture at steep out, and 15°C in ture at steep out and were germination. Error bars indicate the standard error of the mean (n = 3). held at 15 °C throughout germination. It is clear malting hull-less barleys as their acrospires are largely rethat Odyssey is again unique, having low generation of solmoved in the de-culming process post malting, resulting in uble protein and overall low β-glucan. very low levels in the cleaned finished malt. As every system is unique and the variables are many, maltsters using GN-producing varieties who desire lower GN levels in malt DISCUSSION can use the information provided here as a starting point Varieties show differences in the production of GN that for dialing in their own procedures. Utilizing lab assessare also dependent on the malting regime. Of the five lines ment of GN levels to determine what practices will yield tested, Buzz was found to be the least suitable for use if a the best overall results will be a key metric. maltster is interested in maintaining low GN levels. Synergy and Metcalfe, having more moderate production levels of GN while also maintaining reasonable levels of β-glucan CONCLUSION and soluble protein at shorter germination times, could be North American breeding programs such as Montana candidate varieties for maltsters and distillers unable to use State University have started making crosses to integrate the few non-GN varieties currently grown in North Amerthe EPH-null trait into locally adapted varieties, while ica: Genie, Odyssey, and Full Pint. Low levels of GN were also utilizing tools such as the EPH KASP marker (availobtainable using Hockett, however, this variety is known able through Heriot-Watt) to streamline the selection proto be slow modifying. Utilizing Hockett and managing for cess. However, ubiquitous availability of non-GN lines in low GN would likely produce a malt that is not favorable North America is likely still a decade away. Management when looked at in the light of overall malt quality as paof GN and EC production in distilled whiskeys will be a rameters such as β-glucan would likely be undermodified. collaborative effort between maltsters and distillers and It is highly likely that there are measurable interactions will require both communication and education to accombetween the treatments tested here, i.e. combining lower plish. The information provided here is designed to be an temperature with shorter germination will have compleinformative starting point. Maltsters not having access to mentary effects to further lower GN production. Due to non-GN varieties but wanting to effect maximized control time and space constraints we were unable to test a fully over GN production will find that GN quantification is an factorial experiment to understand these potentially benimportant tool for developing best practices within their eficial interactions. In addition, the malting control measpecific production system. sures assessed here are common broad-stroke avenues for controlling level of modification while other management ACKNOWLEDGMENT options may have utility, such as restricted ventilation, Thank you to Jeffrey M. Irvin, the Department Chair for pressure treatments (i.e. wet casting), and use of abscisBrewing, Distillation, and Fermentation at A-B Technical ic acid [5]. Another interesting approach for producing Community College in Candler, North Carolina for his low-GN malts but not explored here is the potential for THE JOURNAL OF DISTILLING SCIENCE

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insights and topic review.

[9] Ehlert, M.; Jagd, L. M.; Braumann, I.; Dockter, C.; Crocoll,

REFERENCES [1] Morrall, A. T. B.; P.; Britain, O. B. O. T. M. A. O. G.

Determination of Repeatability and Reproducibility of a New Rapid Enzyme Method for the Determination of Glycoside Nitrile in Malted Barley. Journal of the Institute of Brewing 1996, 102 (4), 245-247. DOI: 10.1002/j.20500416.1996.tb00908.x.

[2] Nielsen, K. A.; Olsen, C. E.; Pontoppidan, K.; Møller, B.

L. Leucine-Derived Cyano Glucosides in Barley. Plant Physiology 2002, 129 (3), 1066-1075. DOI: 10.1104/ pp.001263.

[3] Swanston, J. S. Quantifying cyanogenic glycoside

production in the acrospires of germinating barley grains. Journal of the Science of Food and Agriculture 1999, 79 (5), 745-749. DOI: 10.1002/(SICI)10970010(199904)79:5<745::AID-JSFA245>3.0.CO;2-E.

[4] Stuart Swanston, J.; Thomas, W. T. B.; Powell, W.; Young, G.

R.; Lawrence, P. E.; Ramsay, L.; Waugh, R. Using molecular markers to determine barleys most suitable for malt whisky distilling. Molecular Breeding 1999, 5 (2), 103-109. DOI: 10.1023/A:1009606705925.

[5] Cook, R.; McCaig, N.; McMillan, J. M. B.; Lumsden, W. B.

C.; Motawia, M. S.; Møller, B. L.; Lyngkjær, M. F. Deletion of biosynthetic genes, specific SNP patterns and differences in transcript accumulation cause variation in hydroxynitrile glucoside content in barley cultivars. Scientific Reports 2019, 9 (1), 5730. DOI: 10.1038/s41598-019-41884-w.

[10] Miller, G.H., Whisky Science: A Condensed Distillation.

2019, New York, NY: Springer.

[11] Dusemund, B.; Rietjens, I. M. C. M.; Abraham, K.; Cartus,

A.; Schrenk, D. Chapter 16 - Undesired Plant-Derived Components in Food. In Chemical Contaminants and Residues in Food (Second Edition), Schrenk, D., Cartus, A. Eds.; Woodhead Publishing, 2017; pp 379-424.12.

[12] Selmar, D. Cyanide in Foods. In Phytochemicals in Human

Health Protection, Nutrition, and Plant Defense, Romeo, J. T. Ed.; Springer US, 1999; pp 369-392. DOI 10.1007/978-14615-4689-4_14.

[13] Bortoletto, A.; Alcarde, A. Assessment of chemical quality

of Brazilian sugar cane spirits and cachaças. Food Control 2015, 54. DOI: 10.1016/j.foodcont.2015.01.030.

[14] Bringhurst, T. A. 125th Anniversary Review: Barley

research in relation to Scotch whisky production: a journey to new frontiers. Journal of the Institute of Brewing 2015, 121 (1), 1-18. DOI: 10.1002/jib.192.

Ethyl Carbamate Formation in Grain-based Spirits: Part III. The Primary Source. Journal of the Institute of Brewing 1990, 96 (4), 233-244. DOI: 10.1002/j.2050-0416.1990. tb01032.x.

[15] Riffkin, H. L.; Wilson, R.; Howie, D.; Muller, S. B. Ethyl

[6] Aylott, R. I.; Cochrane, G. C.; Leonard, M. J.; MacDonald,

[16] Riffkin, H. L.; Wilson, R.; Bringhurst, T. A. The Possible

L. S.; MacKenzie, W. M.; McNeish, A. S.; Walker, D. A. Ethyl Carbamate Formation in Grain Based Spirits: Part I: Post-distillation Ethyl Carbamate Formation in Maturing Grain Whisky. Journal of the Institute of Brewing 1990, 96 (4), 213-221. DOI: 10.1002/j.2050-0416.1990.tb01030.x.

[7] Mackenzie, W. M.; Clyne, A. H.; MacDonald, L. S. Ethyl

Carbamate Formation in Grain Based Spirits: Part II The Identification and Determination of Cyanide Related Species Involved in Ethyl Carbamate Formation in Scotch Grain Whisky. Journal of the Institute of Brewing 1990, 96 (4), 223-232. DOI: 10.1002/j.2050-0416.1990.tb01031.x.

[8] Mander, L.; Liu, H.-w. Comprehensive Natural Products

II: Chemistry and Biology. Vol. 1. 2010, Amsterdam, Netherlands: Elsevier.

Carbamate Formation in the Production of Pot Still Whisky. Journal of the Institute of Brewing 1989, 95 (2), 115119. DOI: 10.1002/j.2050-0416.1989.tb04618.x. Involvement of Cu2+ Peptide/Protein Complexes in the Formation of Ethyl Carbamate. Journal of the Institute of Brewing 1989, 95 (2), 121-122. DOI: 10.1002/j.20500416.1989.tb04619.x.

[17] Jaskula-Goiris, B.; De Causmaecker, B.; De Rouck, G.;

Cooman, L.; Aerts, G. Detailed multivariate modeling of beer staling in commercial pale lagers. BrewingScience 2011, 64, 119-139.

[18] Elmaghraby, E.A., A. Karim, Adapted from Malt Whisky

Manufacture 1 & 2, in Food and Beverage Service. 2012, Food and Beverage Service: http://fb.6te.net/whisky.html. p. Diagram of the whisky making process.

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ORIGINAL PAPER

Investigating Grain-on Malt Whiskey Production Using Naked Barley James Burns1*, Calum Holmes2, Brigid Meints3, and Scott Fisk3 1 The Family Jones, LLC, Denver, CO 2 International Centre for Brewing and Distilling, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, United Kingdom 3 Department of Crop and Soil Science, Oregon State University, 3050 SW Campus Way Corvallis, OR 97331

The ability to produce malt whiskey using grain-on production methods may benefit American craft spirit producers who lack the capacity to separate grains from the wort prior to fermentation and distillation. Off-flavors thought to be derived from barley husk material have prevented distillers from producing whiskey made entirely from malt with grain-on production methods. In the present study, the impacts of using a huskless, naked barley to produce grain-on malt whiskey was investigated. New make spirit was produced at laboratory scale using malt from the covered barley variety Lightning and naked barley variety Buck. The level of esters, higher alcohols, and total polyphenols was measured in the new make spirit. Distillate made from naked barley malt (50% ABV) had a total fusel oil concentration of 2,767 mg/L while whiskey made from covered barley malt had a higher total fusel oil concentration of 3,128 mg/L. Ester levels between the two spirits were similar, with levels of ethyl acetate measuring 7.15 mg/L in the whiskey made from naked barley malt and 7.68 mg/L in the whiskey made from husked barley malt. No polyphenols were detected in either spirit. The new make spirit was also subjected to sensory analysis in the form of a triangle test and quantitative descriptive analysis. Panelists were able to detect a difference between the samples, and whiskey made from naked barley malt was perceived to have a reduction in cereal, feinty, and pungent character. Additionally, despite the naked barley being a GN producer, processing during malting reduced GN to a level associated with non-producing varieties.

INTRODUCTION Naked barley (Hordeum vulgare) has been studied as a raw ingredient for the production of malt whiskey due to the potential it has to increase extract yields while reducing shipping costs, spent grain quantities, and polyphenol levels [1, 2]. All of these advantages relate to the removal of the barley hull during threshing. The lack of an adhering hull is the phenotypic result of a recessive allele at the nud gene located on chromosome 7H [3, 4]. The lack of hull results in naked barley consisting of proportionally more starch, protein, and β-glucan than covered barley [5, 6]. Naked barley is typically used only for food and animal feed, as the hull is important for efficient lautering during production of most malt whiskey and beer [4]. In traditional production of malt whiskey, grains are processed THE JOURNAL OF DISTILLING SCIENCE

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KEYWORDS Grain-on barley malt distilling whiskey American Single Malt

with a roller mill and separated from the wort prior to fermentation, here the husk is required as it forms a vital filter bed [7]. This process differs from the production of American whiskeys where the majority of the mash bill is typically corn and rye, both of which lack a husk; grains are hammer milled and remain in the mash through to distillation [8]. Limitations exist to producing malt whiskies using grain-on techniques as fermenting on the husks results in over extraction of husk materials and produces undesirable grainy characteristics in the new make spirit [9]. The husk accounts for nine to 14 percent of the dried weight of covered barley [4, 10, 11] and is composed primarily of holocellulose, hemicellulose, and lignin [11, 12]. Absence of the husk results in a reduction of the total polyphenols present in barley [1, 13]. The absence of the husk may also increase the susceptibility

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of the embryo and acrospire to damage [14, 15]. The proportionally higher starch levels in naked barley result in increases in extract yield of three to five percent [14] and by tailoring malting procedures, malt extract and predicted spirit yield (PSY) can be optimized [16]. High quality malt can be obtained from naked barley by adjusting the steeping, germination, and kilning methods [14, 17]. Many studies have shown that naked barley requires a shorter steeping time than covered barley [2, 11, 16, 17]. One possible mechanism to explain this phenomenon is that removal of the husk allows the grain to swell more freely [11]. Shorter steeping cycles may result in time, water, and cost savings [15, 18]. Naked barley has been found to contain more nitrogen than covered barley grown under the same fertilization treatment [19]. Due to the higher nitrogen content, longer germination times are likely needed for naked barley to achieve peak PSY [19] and reduce β-glucan to acceptable levels [2]. Germination times of four and five days have been reported for optimal PSY [2, 15, 16]. Kilning naked barley malt at lower temperatures both initially and during curing is thought to slow enzyme inactivation and result in malt with reduced β-glucan levels and increased α-amylase activity [14]. High β-glucan levels can lead to increased wort viscosity [5, 14, 19] and decreased friability [20]. Increasing the steeping time and temperature during malting can lead to the reduction of β-glucan levels [21]. β-glucan levels in naked barley are elevated for two main reasons: (1) Removal of husk proportionally increases β-glucan, which is predominantly associated with endosperm cell wall tissues [19]. (2) Naked barley has been bred for food and not for malt production; elevated β-glucan levels are seen as a positive attribute in barley destined for human consumption [4]. Even when compared to acid-dehusked malt, naked malt was found to contain more β-glucan [5]. Embryo damage prior to malting may also contribute to elevated β-glucan levels because dead kernels do not modify. The role polyphenols play in beer is well understood. Polyphenols contribute to astringency and bitterness [22]. Total polyphenol levels decrease as the husk fraction in the wort decreases [1]. Reducing polyphenols leads to a reduction in harsh bitter flavors [23]. Milling conditions impact the extraction of polyphenols. Extraction is reduced if the husk remains largely intact [24], while fermenting on fine husk particles can lead to off flavors [9]. Phenols are leached from the husk during mashing [12], and increased contact between grist and wort increases extraction [25, 26]. The level of fatty acids in wort also increases with prolonged husk contact [27, 28]. Malt whiskey made from naked barley may have reduced levels of ethyl carbamate. Ethyl carbamate is a carcinogen found in distilled spirits and has been regulated in many 16

countries around the world [29]. Ethyl carbamate is primarily derived from the epiheterodendrin (EPH) found in malted barley [30]. EPH — a glycosidic nitrile (GN) — is produced in the acrospires of germinating barley [31]. The amount of EPH a barley produces is variety specific, with some varieties producing no measurable levels [30]. While Scotland has committed to only approve barleys that are non-producers of EPH for whiskey production [30], LCS Odyssey is currently the only variety on the American Malting Barley Association’s (AMBA) list of recommended barleys that is a non-producer [32]. In naked barley, the unprotected acrospire is removed during deculming. The removal of the acrospire during the deculming of naked barley may reduce the level of EPH in the malt and may lower the level of ethyl carbamate in the new make spirit. This may prove to be an important advantage in the American market. Within the industry, there has been an expectation that whiskey produced using naked barley would contain lower overall concentrations of polyphenolic compounds as compared to spirit derived from typical husked barley, but these potential differences have not yet been addressed in the published literature. Differences have been expected to arise from the removal of the husk and acrospire, and from other physicochemical differences (grain composition, total nitrogen, barley metabolites) that have previously been identified in naked barley varieties [33, 34] many of which are known to contributory to aroma-active volatile compounds such as esters and higher alcohols. The present research evaluates the compositional and sensorial impacts for use of naked barley during production of malt whiskey.

METHODS MALT PROCESSING

The naked barley variety Buck (Figure 1a) and covered variety Lightning (Figure 1b) were grown at Goschie Farm (Silverton, Oregon) and harvested in 2019. Both varieties were malted using Oregon State University’s pilot malting system in 91kg batches. The thousand corn weight of the finished malt was 30.2g for Buck and 49.4g for Lightning on a dry weight basis. Malting conditions were optimized for each variety (Table 1), based on grain quality data and the work of Craine et al. [35]. The Lightning cultivar was subjected to shorter steeps and longer air rests to compensate for water sensitivity (Water sensitivity: Lightning 38 percent, Buck three percent; Germinative energy: Lightning 99 percent, Buck 98 percent; measured using ASBC Methods of Analysis Barley-3C). The steep out moisture content was 47% for Buck and 42% for Lightning. The barley was sprayed with water THE JOURNAL OF DISTILLING SCIENCE

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every six hours during the first day of germination in order to reach a target moisture content of 49% for Buck and 47% for Lightning, requiring one and three sprays respectively. Grain was turned every six hours throughout germination. Moisture content at the end of germination was 46.4% for Buck and 44.7% for Lightning. To determine that suitable modification had been achieved, grains were checked manually for steely ends. Analysis of the malt was conducted by Hartwick College Center for FIGURE 1 Malted barley samples a) Buck naked barley malt b) Lightning covered barley malt. Craft Food and Beverage (Oneonta, New York) using American Society of Brewing Chemists (ASBC) PRODUCTION OF NEW MAKE SPIRIT Methods [36]. Hartwick College also analyzed the glycosidic nitrile levels in the malt samMashing, fermentation, and distillation was carried out ples using Analytica EBC method 4.21 [37]. Full Pint was in triplicate for all samples following a random producused as a negative control for glycosidic nitrile while Copetion order. Malt was milled using a hammer mill with a land was used as a positive control. 0.198cm screen. Infusion mashing was completed in a 38L insulated beverage dispenser. Mashing consisted of a single conversion step at 65°C. Malt (3kg) was combined with TABLE 1 Malting regime for Buck and Lightning barley. strike water (12kg) at 68°C. The liqueBUCK LIGHTNING faction enzyme HiSTEEPING tempase 2XL (KerTIME (H) TEMP. (°C) TIME (H) TEMP. (°C) ry Ingredients, Co. Steep 1 10 16 5 18 Cork, Ireland; a BaAir rest 1 12 16 16 16 cillus licheniformis derived α-amylase) Steep 2 10 16 5 18 was added at a rate Air rest 2 10 16 15 16 of 0.535ml/L and Steep 3 6.5 16 5 18 the mashes were alGERMINATION lowed 60 minutes for conversion [38]. TIME (H) TEMP. (°C) TIME (H) TEMP. (°C) After stirring to Conditions 120 18 96 18 combine, samples KILNING were left unagitatAIR-ON AIR-OFF AIR-ON AIR-OFF TIME (H) TIME (H) ed for the duration TEMP. (°C) TEMP. (°C) TEMP. (°C) TEMP. (°C) of mashing. On Stage 1 10 50 43 10 50 43 average, the mash Stage 2 3 60 56 3 60 56 dropped 3°C during conversion. MashStage 3 3 65 61 3 65 61 es were cooled to Stage 4 2 70 64 2 70 65 21°C±1°C using a Stage 5 2 80 71 2 80 71 copper immersion wort cooler. Water Stage 6 5 90 78 5 90 79 THE JOURNAL OF DISTILLING SCIENCE

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was added to standardize the original gravity to a specific gravity of 1.061. All fermentations were carried out in 19L HDPE fermenters sealed with lids that had been perforated with one 3mm hole to allow off gassing. At the onset of fermentation, 0.35ml/L of Bioglucanase GB (Kerry Ingredients, Co. Cork, Ireland; Trichoderma longibrachiatum derived β-glucanase) [39], 0.35ml/L of Amylo 300 (Kerry Ingredients; fungal amyloglucosidases)[40], 0.71ml/L of FermCap S (Kerry Ingredients; Dimethylpolysiloxane) [41], and 0.57g/L of M type yeast was added. Specific gravity, pH, and temperature was measured at the start of fermentation and daily throughout the four-day fermentation period. Wash was filtered through a fine mesh before analysis. Wash yield ranged from 15.9 to 17L. The resulting wash was double distilled using a 3L glass benchtop pot still. Copper mesh (15g) was added to the vapor path to catalyze reactions with sulfur. Heat was applied using a 100B TM112 heating mantle (Glas-col LCC, Terre Haute, Indiana) controlled by an Aldrich Digitrol II temperature controller (Millipore Sigma, St. Louis, Missouri) set to 96°C. For stripping distillations, 3L of wash was distilled until the distillate run-off dropped below an alcohol by volume (ABV) of five percent. The average flow rate of distillate from the condenser was 7.5 ml/min. Three stripping runs were performed for each fermentation and combined ahead of the spirit distillation. For the spirit distillations, 100ml of distillate was collected as heads (foreshots) and discarded. A hearts (main cut) fraction was collected until the ABV dropped below 50%, at which point the run was concluded without the collection of tails. Vapor temperature at the top of the still and ABV was recorded at five-minute intervals after the onset of runoff for both stripping and finishing distillations. ABV was measured using an Anton Paar DMA 35 density meter (Anton Paar, Graz, Austria). For each trial group, new-make spirits from the three replications were combined for analysis. ANALYSIS OF NEW MAKE SPIRIT

The new make spirit was subjected to both analytical and sensory analysis. A spectrum of tests included the determination of polyphenol, higher alcohol, and ester concentrations and was completed by Brewing and Distilling Analytical Services (Lexington, Kentucky). Total polyphenols were assessed using the colorimetric — spectrophotometric method described by ASBC Methods of Analysis Beer35 [42]. New make was assessed in duplicate at dilutions of 50% ABV and 5% ABV. Higher alcohols and esters were measured using gas chromatography with flame-ionization detection (GC/FID); new make was diluted to 50% ABV and assessed in duplicate. Sensory analysis included a triangle test and quantitative descriptive analysis, these were used to assess overall 18

sensory differences and more granular spirit aroma profile attributes respectively. For both tests, samples were bottled and provided to panelists with instructions for remote assessment. Sensory analysis guidelines laid out by Jack (2003) were followed, including diluting all samples to 20% ABV. Samples were presented as 50ml aliquots labeled with three-digit codes that were generated randomly. Triangle testing was carried out following methodology of the British Standards Institute [43] as has been done in recent studies [44]. Testing was completed by 32 individual assessors. The group of assessors was composed of professionals and academics with beverage or barley breeding experience. Quantitative descriptive analysis for the new make was carried out using methods described in ISO 6564:1985 [45]. Sensory attributes were selected from previous descriptive analysis studies of new make malt whiskey [46, 47]: pungent, phenolic, feinty, cereal, estery, oily, sulfury, and clean. The panel consisted of eight distillers with experience tasting new make spirits. Assessors were TABLE 2 Quantitative descriptive asked to nose and taste analysis scale. the samples. Assessors were asked to rank the SCORE PERCEPTION chosen attributes on a 0 Not present scale of 0-5 (Table 2) [45]. 1 Just recognizable A Scotch whiskey flavor wheel [8] was provided 2 Weak to panelists to help focus 3 Moderate descriptions. 4 Strong 5 Very strong

RESULTS AND DISCUSSION

PRODUCTION CONSIDERATIONS

Malt was produced from both Buck and Lightning barley (Table 3). It was necessary to malt each variety under differing conditions (Table 1) to achieve acceptable modification and friability. In the finished malts, differences were seen in the levels of extract yield, β-glucan, protein, and diastatic power (DP). As expected, Buck malt had elevated extract yield (89.3% compared to 82.2%) and β-glucan levels (102 mg/L compared to 44mg/L). The likely causes for these results was the proportional increase in starch due to the removal of the husk. No processing issues (scorching or foaming) were seen in the lab scale trials due to elevated β-glucan levels. Protein levels differed between Buck (8.8 percent) and Lightning (10.6 percent), but the associated free amino nitrogen (FAN) levels for Buck (140 mg/L) and Lightning (172mg/L) were within the AMBA specified range of 140-190mg/L [48]. Diastatic power also differed but use of exogenous enzymes during mashing and THE JOURNAL OF DISTILLING SCIENCE

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TABLE 3 Quality analysis of Buck and Lightning malt. A single replication was run for each quality parameter following ASBC methods. QUALITY PARAMETER

BUCK

LIGHTNING

Moisture Content (%) Friability (%) Extract (%) Color (°SRM) β-glucan (mg/L) Total Protein (%) Soluble Protein (%) S/T (%) FAN (mg/L) DP (°L) Alpha Amylase (DU) Filtration Clarity pH

5.0 96.4* 89.3 1.35 102.0 8.8 3.92 44.5 140.0 77.0 45.0 Normal Hazy 5.78

4.2 98.2 82.2 1.44 44.0 10.6 4.59 43.3 172.0 120.0 46.4 Normal Clear 5.81

*Completed by Oregon State University.

FIGURE 2 Fermentation profile for Lightning covered barley malt and Buck naked barley malt. Results are the mean of triplicate analyses ± standard deviation.

fermentation perhaps reduced impact on processing. statistical difference between the two groups. A two-tailed The specialized malting parameters needed to create T test with a p-value of 0.001 showed a significant differhigh quality malt from naked barley may increase costs. In ence in the wash volumes between the varieties with Buck alignment with previous research by Edney and Langrell malt washes averaging 16.9L and Lightning malt washes (2004), the malt produced for this project needed five days averaging 16L. Wash volumes differed due to standardizato modify completely. Drum malting naked barley may be tion of the original gravity. problematic since the embryo and acrospire are more susDuring the stripping distillations (Figure 3), distillate ceptible to damage [14]. In addition, premiums are often from Lightning malt mashes were consistently collected paid to growers for malt barleys that yield less than feed at a lower proof than distillate collected from Buck malt barleys [11]. Buck barley showed yields that were lower mashes. This resulted in than covered barley (6,485 the temperature at the top kg/ha compared to an avof the still reading higher erage of 7,022 kg/ha for at any given point during the covered checks). Howthe distillation for Lightever, when yields were ning, and the stripping adjusted by 12 percent to distillations concluding account for husk removal, 10 minutes earlier than Buck yielded slightly more Buck stripping distillathan the covered barleys tions. Buck malt washes studied [6]. The premiums produced significantly that Buck will command more liters of absolute are currently unknown. alcohol (LAA) during Fermentations with stripping runs (Table 4). these malts followed simFinishing distillations ilar trajectories (Figure 2). proceeded similarly (FigBoth malts resulted in a ure 4); From 9L of wash, FIGURE 3 Temperature and ABV profiles during stripping distillation wash with an average final Buck malt produced on for Lightning and Buck barley malts. Results display mean measurement alcohol content of 8.1±0.2 ± standard deviation. Nine replicates were conducted for each test group. average 0.5 LAA of new % ABV. There was no make spirit compared to THE JOURNAL OF DISTILLING SCIENCE

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0.45 LAA for Lightning malt — a significant difference (P = 0.003) (Table 4). Previous research on naked barley has touted increased yields as one of the primary benefits [2]. Results from this experiment are aligned with previous works. Producing new make spirit from naked barley using grain-on methods resulted in an 11 percent increase in LAA (Table 4). This increase in efficiency may offset premiums associated with procuring and malting naked barley. The size and production capabilities of a distillery that is interested in producing malt whiskey will also impact the economics of using naked malt. For a distillery with low throughput and no separation capabilities — as may be expected for a craft distillery producing several different styles of American whiskey — the capital cost of installing separation and milling equipment to produce malt whiskey using traditional methods may be high. In this case, paying a premium for naked barley may well be justifiable. Conversely, if the capital costs are more reasonable or the operation is large or focused solely on making malt whiskey, using naked barley may not be the most economical option.

TABLE 4 Yield data collected during stripping and finishing distillations. Low wines originating from the same fermentation were aggregated. Low wine data is presented as the average amount collected from each of the three fermentations ± standard deviation. New make data is the average from the three finishing runs ± standard deviation.

Low Wines volume (ml) Low Wines %ABV Low Wines LAA New Make volume (ml) New Make %ABV New Make LAA

BUCK

LIGHTNING

2166±53 31.9±0.8 0.69±0.1 696±6 72.4±0.1 0.50±0.03

2081±45 30.5±0.4 0.64±0.2 627±19 72.3±0.1 0.45±0.1

ETHYL CARBAMATE IN NAKED MALT

The glycosidic nitrile levels (Table 5) found in Buck malt were less than 0.5 g/tonne, the level at which barley varieties are said to be non-producers. The Lightning malt tested in line with low producers (between 0.5-1.5 g/tonne). Levels of glycosidic nitrile in Buck malt are similar to the levels seen in the variety Odyssey, the only EPH non-producing malt variety available in the United States [49]. The acrospire of germinated Buck barley was identified as an EPH producer using the methods of Cook and Oliver [50]. The removal FIGURE 4 Average temperature, ABV, and spirit volume collected during of the acrospire during deculming likely contribfinishing distillations for Lightning covered barley malt and Buck naked barley uted to the malt testing lower in glycosidic nitrile. malt. Error bars show standard deviation. Three replications were conducted for Lightning has glycosidic nitrile levels similar to each test group. the widely used varieties such as CDC Copeland, USDA Endeavor, and AC Metcalfe [49]. Although levels of ethyl carbamate in whiskey are not currently regulated in the United States, it is a known TABLE 5 Glycosidic nitrile levels in Buck and Lightning malt. carcinogen. Maximum levels have been set in Canada (150 Sample GN producer status was defined as: Non-producer (<0.5 ppb), Germany (400 ppm), and the Czech Republic (150 ppb) g/tonne), Low-producer (0.5-1.5g/tonne), High-producer (>5g/ [30]. The reduction of ethyl carbamate associated with naked tonne). A single replication was conducted for each sample. malt may allow producers to take advantage of new export markets and protect themselves against the possibility of future regGLYCOSIDIC NITRILE PRODUCER ulations. SENSORY DIFFERENCES

While distilling malt whiskey from naked barley may offer 20

Buck Lightning

(G/TONNE)

STATUS

0.2 1.4

Non-producer Low-producer

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increased efficiency and reduction of ethyl carbaTABLE 6 Analysis of new make spirit at 50% ABV. Values are presented as the mate, evidence from the triangle test, analytical average of duplicate analysis. analysis, and quantitative descriptive analysis point to differences between new make spirit made from NMS VOLATILE COMPONENT BUCK LIGHTNING naked and covered barley. In the triangle tests, 18 of Acetaldehyde (mg/L) 7.15 7.68 32 participants correctly identified the sample that Ethyl Acetate (mg/L) 23.1 24.6 was different from the others. This corresponds to an α-risk of 1 percent [43]. This indicates strong evMethanol (mg/L) n.d. 12.4 idence of an apparent difference. It has been shown n-Propanol (mg/L) 138.8 274.65* that beers made from different barley varieties have Isobutanol (mg/L) 777.1 846.5 perceptible variations in sensory attributes [33, 51]. 1-Butanol (mg/L) 3.8 3.66 However, the impact of variety on flavor is less sigActive and Iso-amyl Alcohol (mg/L) 1846.8* 2003.7* nificant than the impact of malting and yeast type [51]. Importantly for this study, the level of phenolic Furfural (mg/L) n.d. n.d. compounds may vary substantially between barley Total Fusel Oils (mg/L) 2766.5 3128.3 varieties [52]. In comparing the flavor of malt whisTotal Polyphenols (mg/L) n.d. n.d. kies made from a naked and covered barley, some n.d. = not detected flavor differences may be due to varietal differences. * = outside of instrument’s calibration range Analysis of the new make spirit (Table 6) indicated that the whiskies had similar levels of acetalindicates that spirit derived from husked barley was eledehyde, ethyl acetate, and 1-butanol. Whiskey made from vated in phenol character as compared to that produced Lightning was higher in methanol, n-propanol, isobutanol, using naked barley. Husk is not the sole source of phenoactive and iso-amyl alcohol, and total fusel oils. Polyphelic compounds in barley and other tissues may potentially nols and furfural were not detected in either sample. contribute to phenolic sensory characteristics, for instance It has previously been suggested that polyphenols extracthydroxycinnamic acids (ρ-coumaric and ferulic acids) can ed from the husk during mashing and fermentation would be derived from plant cell walls found throughout the barbe present in the new make spirit made from covered barley grain, from here they can be extracted during mashley and that they would contribute to bitter and astringent ing [53]. Through enzymatic or thermal reactions, these off-flavors. In the present research, results do not support phenolic compounds with high flavor thresholds (such as this hypothesis as polyphenols were not detected in either ferulic acid) can be decarboxylated to compounds with new make spirits (Table 6) and QDA analysis (Figure 5) low flavor thresholds (such as 4-vinyl guaiacol)[54]. 4-vinyl guaiacol is considered a desirable volatile in rye whiskies that contributes to the characteristic spiciness common to these spirits [55]. ρ-coumaric acid, ferulic acid and vanillin are respectively converted to 4-ethylphenol, 4-ethylguaiacol and 4-methyl-guaiucol by various strains of yeast and bacteria (Suomalainen and Lehtonen, 1979)[56]. For example, Brettanomyces yeast strains will convert phenols from malt into volatiles such as 4-ethylguiacol (Clove/smoky aroma) and 4-ethylphenol (smoky/phenolic aroma) (Vanderhaegen et al., 2003). As bacteria and wild yeast are often encouraged during whiskey fermentation through the use of wooden fermenters and unsterilized washes (Reid et al., 2020), these phenol-derived volatiles are likely to be found in new make whiskey. Strains of distiller’s yeast are also known to produce 4-vinyl guaiacol [57] — the strain used in this experiment being a common choice for distillers [57, 58]. InFIGURE 5 Quantitative descriptive analysis of whiskies made with Buck and terestingly, it has been found that mixed cultures of Lightning malt. Results are the average of rankings by eight individual assessors. yeast and lactic acid bacteria result in less volatile THE JOURNAL OF DISTILLING SCIENCE

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phenols at the end of fermentation than do pure strains of yeast [56]. Rye varietal trials conducted by Michigan State University (East Lansing, MI) found a positive correlation between protein levels in different rye varieties and the levels of 4-vinyl guaiacol in new make rye whiskey [55]. The levels of 4-vinyl guaiacol and other phenolic-derived volatiles in new make spirit from this experiment were not tested. Further investigation into the levels of these compounds is needed to determine how they influence the flavor differences observed in this experiment. Furfural is another flavor active compound derived from cell wall and husk material [27, 59]. At levels between 20 and 30 mg/L, furfural has been said to add sweet, grainy, and nutty flavors in malt whiskey and is thought to influence the hotness of a spirit [59]. Typical levels seen in Scotch whisky are 1.5-9.95mg/L Similar to polyphenols, furfural was not detected in the new make spirit (Table 6). Previous studies have indicated that furfural levels in whiskey are derived from wood during maturation [60], with levels increasing rapidly during the first six months [61]. Quantitative Descriptive Analysis (QDA) (Figure 5) indicated that Cereal was the most intense attribute in both samples; the average rating for cereal character was 2.9 in new make made from Buck malt and 3.4 in whiskey made from Lightning malt. Bathgate (2016) notes that excessive concentrations of amino acids and hydrolysed lipids in grain-on fermentations likely result in different higher alcohol profiles. He notes that whiskies made using these techniques have grainy, vegetal, and sulphury notes [9]. New make spirit made from Buck malt had lower levels of total fusel oils (2766.5 mg/L) than new make spirit made from Lightning malt (3128.3 mg/L)(Table 6) and reduced cereal, feinty, and pungent characteristics (Figure 5). Lightning new make spirit had n-propanol levels (274.65 mg/L) within the previously observed range of 180-605 mg/L [62] but higher levels of isobutanol (846.5mg/L) than had previously been observed (280-470 mg/L) [62]. Buck malt whiskey tested lower than the previously observed range for n-propanol (138.8mg/L) and higher than the range for isobutanol (777.1 mg/L). FAN values between 150-180 mg/L are typically specified for malt destined for whiskey production [7]. Increased levels of FAN are associated with increased production of higher alcohols and esters during fermentation [33]. The Lightning malt used for this experiment fit within the acceptable range at 172 mg/L while the Buck malt used was just below acceptable levels at 140 mg/L (Table 3). Accordingly, Lightning produced higher levels of higher alcohols and esters (Table 6). Along with lower FAN levels in general, naked barley may have reduced levels of specific amino acids that are required by yeasts [63]. While reduction in specific amino acids may limit fermentability, no such issue

was observed during this trial — both varieties had a terminal specific gravity of 1.0 (Figure 2). Naked barley malt had reduced FAN and elevated β-glucan as compared to husked malt, this suggests reduced modification of endosperm. It is interesting that the naked barley malt had a higher extract potential (89.3%) than husked malt (82.2%), perhaps as a result of the increased proportion of endosperm tissue. Isoamyl alcohol makes up 40-70 percent of the higher alcohols in alcoholic beverages [64]. Both whiskies in this study fall in that range with active and isoamyl alcohol representing 64 percent of total fusel oils in whiskey made from Lightning malt and 66 percent in whiskey made from Buck malt (Table 6). High levels of isoamyl alcohol are perceived as off flavors [57] and may have translated into the increased perception of feinty and pungent character in the whiskey made from Lightning malt (Figure 5). During maturation, the concentration of fusel oils in the whiskey is relatively unchanged; increases are accounted for by varying volatility of distillate components and evaporation from the barrel [65]. While ester levels (Table 6) measured similarly between the two malts — 23.1mg/L for Buck and 24.6 mg/L for Lightning — whiskey made from Lightning was perceived to have more ester character (Figure 5); assessors ratings averaged 2.4 for Lightning and 2.0 for Buck. Esters contribute solvent-like and fruity character to spirits [66]. Previous research has shown that there isn’t a direct relationship between chemical composition and perceived flavor due to interplay between compounds and masking effects [67]. Removal of the husk may contribute to a reduction in ester production by reducing the level of beneficial microorganisms. At low levels, bacteria may improve spirit quality [68]. Lactic acid bacteria found on grain surfaces can contribute to the acidification of mash and have a positive effect on whiskey flavor [58, 69, 70]. Specifically, lactic acid bacteria have been shown to increase fruity, floral, and sweet aromas in new make malt whiskey [44]. Whiskey made from Buck barley was perceived to have more prominent sulphur character (Figure 5). The amino acid metabolism of yeast produce sulphur aromas that contribute to the heaviness of a spirit [57]. Sulphur compounds have vegetal, rotten egg, and rubbery aromas [71]. Fermentation temperature, yeast strain, and yeast pitching rate may influence the production of sulphur during fermentation [72]. Sulphur levels are reduced due to reactions with copper in the still [71] — spirits made using a stainless steel still had higher concentrations of dimethyl trisulphide (DMTS) than spirits made using a copper still [47]. Since a glass still with a limited amount of copper packing was used in this experiment, it is unsurprising that some sulphur character is present in the new make whiskey. New make spirit from a copper pot still would likely have lower

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Increased extract yield was achieved in the new make spirit produced from naked barley using grain-on production methods. This aligns with previous studies that have used naked barley to make spirits from filtered worts. Concentration of GN in naked barley was similar to that expected of non-producing barley varieties, perhaps as a result of acrospire removal during malt processing. New make spirit made with naked barley using grain-on techniques had lower levels of higher alcohols than new make spirit made with covered barley under the same conditions. A difference in flavor between the two new make spirits was perceptible on a sensory basis but interestingly whiskey produced using naked barley was not perceived to be reduced in phenolic character as compared to whiskey made from husked barley. Future research is needed to assess the source of perceived differences. Producing malt whiskey from naked barley using grain-on production methods may allow American craft distillers to efficiently produce high quality spirit without investing in new production equipment. The reduced GN levels seen in naked barley malt may open export markets in regions that regulate ethyl carbamate in spirits. ACKNOWLEDGEMENTS

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Benson, A.; Vega, V.; Carey, D.; Thiel, R.; Cistue, L.; et al. Malt Modification and its Effects on the Contributions of Barley Genotype to Beer Flavor. Journal of the American Society of Brewing Chemists 2017, 75 (4), 354-362. DOI: 10.1094/ASBCJ-2017-4976-01.

[52] Zhao, H.; Fan, W.; Dong, J.; Lu, J.; Chen, J.; Shan, L.; Lin,

Y.; Kong, W. Evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties. Food Chemistry 2008, 107 (1), 296-304. DOI: 10.1016/j. foodchem.2007.08.018.

[53] Vanbeneden, N.; Delvaux, F.; Delvaux, F. R. Determination

of hydroxycinnamic acids and volatile phenols in wort and beer by isocratic high-performance liquid chromatography using electrochemical detection. Journal of Chromatography A 2006, 1136 (2), 237-242. DOI: 10.1016/j. chroma.2006.11.001.

[54] Madigan, D.; McMurrough, I.; Smyth, M. R. Rapid

Determination of 4-Vinyl Guaiacol and Ferulic Acid in Beers and Worts by High-Performance Liquid Chromatography. Journal of the American Society of Brewing Chemists 1994, 52 (4), 152-155. DOI: 10.1094/ ASBCJ-52-0152.

the American Society of Brewing Chemists 2020, 78 (4), 260278. DOI: 10.1080/03610470.2020.1795795. D. Origins of Flavour in Whiskies and a Revised Flavour Wheel: a Review. Journal of the Institute of Brewing 2001, 107 (5), 287-313. DOI: 10.1002/j.2050-0416.2001.tb00099.x. Bourbon Whisky Matured at Various Proofs for Twelve Years. Journal of Association of Official Analytical Chemists 1974, 57 (4), 940-950. DOI: 10.1093/jaoac/57.4.940.

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Maturing. Industrial & Engineering Chemistry 1943, 35 (9), 994-1002. DOI: 10.1021/ie50405a013.

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Confirm the Generic Authenticity of Scotch Whisky. Journal of the Institute of Brewing 2010, 116 (3), 215-229, DOI: 10.1002/j.2050-0416.2010.tb00424.x.

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Legge, W. G.; Rossnagel, B. G. Importance of Endosperm Modification for Malt Wort Fermentability1. Journal of the Institute of Brewing 2007, 113 (2), 228-238, DOI: 10.1002/ j.2050-0416.2007.tb00280.x.

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Compounds by Yeast. Journal of the Institute of Brewing 1979, 85 (3), 149-156, DOI: 10.1002/j.2050-0416.1979. tb06846.x.

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Maturing. Industrial and Engineering Chemistry, 1949, 41(3): p. 534-543.

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Whisky Flavour. Journal of the Institute of Brewing 1979, 85 (2), 82-85, DOI: 10.1002/j.2050-0416.1979.tb06830.x.

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Walker, G. Comparison of Three Approaches to Assess the Flavour Characteristics of Scotch Whisky Spirit. Applied Sciences 2021, 11, 1410. DOI: 10.3390/app11041410.

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on spirit character: the lost styles of Scotch malt whisky. Journal of the Institute of Brewing 2019, 125 (2), 200-213, https://doi.org/10.1002/jib.556. DOI: 10.1002/jib.556 (accessed 2022/11/30).

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Investigating Grain-on Malt Whiskey Production Using Naked Barley

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of evolution, experience, and an ongoing entrepreneurial spirit. In Whisky (Second Edition), Russell, I., Stewart, G. Eds.; Academic Press, 2014; pp 39-48.

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compounds during distillation, in Brewing and Distilling. Doctoral Thesis, 1996, Heriot-Watt University: Edinburgh. https://www.ros.hw.ac.uk/handle/10399/1215.

REVIEW

Microfluidics and the Spirits Industry: A Review Tonoy K. Mondal1 and Stuart J. Williams1*

KEYWORDS

1 University of Louisville, Louisville, KY, USA

There is and will always be the need to provide authentic and safe alcoholic beverages. To achieve this goal, researchers are constantly looking for innovative and practical approaches to analyze their samples and control their quality. Quality control can be challenging in the spirits industry due to their production (mashing, fermenting, distilling, aging, packaging) and their complex chemical composition. To assess the quality and safety of alcoholic beverages, a variety of analytical procedures have been developed and are currently in use. Although these laboratory-based approaches offer a high level of sensitivity, they can be both time-consuming and costly. Therefore, it is an ongoing need to advance simpler, faster, more precise, field-deployable, and more sensitive instruments to identify chemicals and abnormalities in alcoholic beverages. We believe many needs can be addressed using microfluidic technologies, sometimes referred to as lab-on-a-chip devices. In this review, we will discuss recent significant advancements in microfluidics for the assessment of alcoholic beverage products. The analysis and viewpoints presented in this study are intended to stimulate continued development of microfluidic devices in the spirits sector and other food safety testing and monitoring fields, benefiting human health and overall well-being.

INTRODUCTION Food composition and its impact on health have produced a need for improved quality control in order to provide authentic and safe alcoholic beverages. To achieve this goal, researchers are constantly looking for innovative and practical approaches to analyze their samples and control their quality. Controlling liquor quality is a significant challenge in the spirits manufacturing industry. The amount of ethanol (ethyl alcohol) in spirits is a significant aspect of assessing its overall quality [1-3]. Besides ethanol and water, organic molecules, namely organic acids, aldehydes, esters, higher or lower order alcohol, and many other compounds, may be present in alcoholic beverages during the brewing, maturation, or distilling process [4]. All these compounds directly affect the quality of the alcoholic beverages in different ways. Thus, to ensure the quality of different spirits, it is very important to determine the quantity and presence of different compounds, including unwanted hazardous material. To ensure the quality and safety of alcoholic beverages, a number of analytical techniques for the examination of spirits components in either the gas and/ THE JOURNAL OF DISTILLING SCIENCE

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Microfluidics Sensing Spectroscopy Analytical systems Whiskey Beverages Authenticity Quality Control

or liquid phase are currently in use. This includes gas chromatography [5-7], high performance liquid chromatography [8,9], mass spectrometry [10-12], infrared or UV-vis spectrometry [13,14], and solid-phase microextraction [15,16]. Although these laboratory-based approaches offer a high level of sensitivity, they can be time-consuming, requiring trained personnel, and can use expensive equipment. Further, many distilleries lack modern analytical equipment and typically use the analytical services of an outside laboratory. Here, findings can take anywhere from some hours to many days, compromising productivity. As a result, there is an ongoing need to create simpler, faster, more precise, field-deployable, and more specific devices for detecting substances in alcoholic beverages in order to ensure quality, avoid adulteration, and ensure safety. We believe many needs can be addressed using microfluidic technologies, sometimes referred to as lab-on-a-chip devices. In this review, we will provide a brief introduction to microfluidics and later describe several microfluidic studies associated with the spirits industry, with an emphasis on analytical techniques and monitoring various target compounds that are important to the quality and safety of alcoholic beverages.

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We will also address how microfluidics can aid in fermentation, maturation, identification, and verification of alcoholic beverages.

MICROFLUIDICS INTRODUCTION

Microfluidic platforms either pump or wick a stream of fluid-(s) through the device or generate and manipulate a series of micro-droplets, the latter referred to as digital microfluidics. Small micro-channels within a device are sometimes referred to as capillaries. Capillary microfluidic systems control the speed and direction of flow by using positive pressure generated by syringe pumps, pressure pumps, gravity, or other approaches [31]. The applied pressure overcomes resistive surface tension and hydrodynamic resistance within the device. If the micro-channel is hydrophilic, then surface tension may wick fluid into the device. Because of current fabrication practices, many microfluidic systems are planar and have channels with rectangular cross-section. Systems can be categorized by how they intersect with other channels, including T-junction [32], Y-junction [33], or cross-junctions [34]. Through careful manipulation of the fluid streams, liquid samples can be under hydrodynamic focusing [35] which can enhance some sensing applications, including flow cytometry. If the fluid streams are immiscible, then droplets can be created and analyzed individually [36] for a rapid analysis of isolated samples. Paper-based microfluidic system is a more recent advancement, using hydrophilic cellulose or other fibers to transport the fluid to different sections of the device, eliminating the need for external pumps [37].

Microfluidics is an interdisciplinary field where a small sample of fluid is transported and analyzed within a miniature device, typically requiring microliters (or less) of the sample. In 1979, the foremost microfluidic technology for gas sensing was created on a wafer made of silicon. It comprised a thermal conductivity detector coupled with a gas chromatograph, a capillary column, and a sample injection system [17]. Ever since, microfluidics has expanded into a variety of domains, including chemistry, biology, medicine, and physical sciences. Microfluidic devices have several benefits, including decreased amount of reagents needed, less waste, and measurement automation [18]. When compared to macroscopic systems, microfluidic devices can perform processes faster while using far fewer chemicals and solvents [19]. The technology allows laboratory testing to be completed in a fraction of the time, varying between hours and minutes, using chemicals as small as microliters or nanoliters. As a result, energy consumption and waste generation are minimized. Owing to its unique properties of microfluidics' small dimensions, which result in a greater surface area-to-volume ratio, elevated surface tension, laminar flow, and improved capillary effects, microfluidic systems have enormous potential for miniaturizing and enhancing existing methods for particular detection, target separation, and assessment [20]. Additionally, advantages such as mobility, sufficiently large sample detection, and a variety of configurations for numerous operational modules are available [21-24]. Microfluidics have been used successfully for a plethora of health science applications, including cell manipulation, sorting, and separating; identification of pathogens, antibodies, and viruses; analysis of secreted compounds, detection of biomarkers, and many more [25]. Microfluidics also has a significant presence in the pharmaceutical industry, including the synthesis of new drugs, drug screening, and the impact of drug dosage on biological samples. Paper-based microfluidic devices have also been used for drug analysis and environmental monitoring [26,27]. Microfluidics have also been used for quality control and analysis in food sciences. For example, devices can monitor a variety of target substances, including chemical hazards and other contaminants detection as pesticides [28]. Microfluidics have also been used to assess emulsifications, quantify nutritional or toxic compounds, detect food pathogens, etc. [29,30].

Microfluidic devices have been manufactured in a variety of ways [38]. Many micro-channel features are sub-millimeter, and such features can be created using a variety of additive or subtractive mechanical, chemical, laser-made, or other types of processes [39]. Materials include ceramics, glass, metals, silicon, elastomers, and thermoplastics. However, the most prominent method for creating microfluidic devices is termed "soft lithography". Soft lithography refers to molding elastomers, which are typically polydimethylsiloxane (PDMS). First, microfluidic features, generally from 10 μm to 1,000 μm in height are patterned on a substrate using photolithography, with Su-8 being the most often used photoresist [40]. Next, an uncured polymer is poured onto these features and a vacuuming is utilized to remove bubbles and for the polymer to conform around the microfluidic features. After curing, the piece is took off the master mold and sealed onto a glass or polymer substrate [40]. In soft lithography, the master mold can be used repeatedly to create many polymer castings of the device. If microfluidic mold features are created from more rigid materials like silicon or metal, the master could be used for hot embossing [41] or injection molding [40,42]. Even though a majority of microfluidic chips are created from polymers, glass-based fabrication methods can be used [43] when its chemically inert properties are favorable

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for sample analysis. The 3D printed microfluidic device is considered the most current innovation in microfluidic technology [44,45]. By selectively curing, depositing, or combining materials in consecutive layers in 3D printing, digital models of microfluidic systems can be created while minimizing waste [46]. Most 3D printed structures are from thermoplastics, but Gal-Or et al. [47] created glass microfluidic devices with dimensions down to 100 µm with outstanding optical quality in tens of minutes using molten soda-lime glass.

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fermentations. Yeast was readily available, and it was inexpensive and simple to procure and use. However, more specialized distilling yeasts with a higher ethanol tolerance and a wider substrate range are more prevalent as a replacement for leftover brewing yeast and are occasionally (but not always) blended with the brewing yeast [48]. Microfluidics could be useful in industry for the selection, and sorting of yeast; several microfluidic approaches to monitor, analyze, and sort yeast are described next. Within a microfluidic device, long-term cell cultivation under different substrate concentrations, i.e., glucose concentrations with individual yeast tracking are achievable. Oliveira et al. [49] demonstrated that selecting growth profiles of free cells using a concentration gradient microfluidic device based on diffusion is an excellent technique for analyzing the growth of Saccharomyces cerevisiae at various concentration of glucose. To create the gradient on the bottom level, 0 g/L and 40 g/L solutions of glucose were injected, and for ten hours, S. cerevisiae growth was observed using time-lapse confocal microscopy along with 30-minute picture acquisition frames. Traditional batch cultivation experiments were also performed to compare the results that showed a similar pattern. Thus, the development of a diffusional concentration gradient enabled researchers to analyze cell behavior across a range of glucose concentrations in a single assay. The kinetic Monod variables were also calculated utilizing low concentrations, which are inaccurate in batch methods due to the limited substrate's consumption over time, making this a more practical and time-efficient procedure than typical submerged

EXAMPLES OF MICROFLUIDICS FOR THE SPIRITS INDUSTRY There are several characteristics of microfluidic analytical devices that can be helpful for the spirits industry. This section highlights several applicable studies and approaches. FERMENTATION

The yeast Saccharomyces cerevisiae uses fermentable carbohydrates to make ethanol, carbon dioxide, and other metabolites, many of which add to the flavor of the alcoholic beverage. As a result, selecting a good yeast is critical for any distillery. Contamination by a range of microorganisms, particularly lactic acid bacteria and wild yeasts, can compromise the final product. But traditionally, little thought was given to this selection, and a locally sourced spent brewing yeast would be used for whisky

(A)

(B)

FIGURE 1 Yeast aging study and yeast sorting using microfluidics. (A) Design and working mechanism of microfluidics chip (i) Optical representation of the device. (ii) Branched trapping channels. (iii) SEM image of trap arrays (iv) Schematic diagram of working mechanism. (v) Single yeast cell showing the mechanism of action. (Scale bar: 10 μm). Reprinted with permission from [50]. (B) Schematic representation of the two-phase microfluidic device. (i) schematic of dual-imaging microscopy system. (ii) Cell sorting performance characteristics are defined. (iii) Three inlets and two outlets completed the chip. Reprinted with permission under a Creative Commons Attribution-NonCommercial 4.0 International License from [57] (https://doi.org/10.1038/s41598-020-65483-2) THE JOURNAL OF DISTILLING SCIENCE

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cultivation procedures. Besides growth rates, the complete lifespan of yeasts, as well as morphological and phenotypical changes in aging, are all factors to consider when choosing the right yeast strain for beverage fermentation. As illustrated in Figure 1A, Jo et al. [50] established a high-throughput yeast aging study chip microfluidic device capable of trapping up to 8,000 separate yeast cells while excluding newly budded daughter cells. They assessed changes in cell morphology and attributes associated with lifespan, including essential cell size, protein subcellular localization, and terminal morphology. This platform enables cells to be held and analyzed under a steady growth setting for the entirety of their life within the microfluidic channel, mitigating the impacts of operator and environmental fluctuations. Existing lifespan analysis have hampered large throughput aging investigations in yeast, but these capabilities substantially remove those constraints. To get more ideas and more research about yeast aging, we refer to the reader a review of articles on yeast aging studies using microfluidic devices [51]. As per their findings, to the present, several microfluidic devices have effectively shown the ability to follow the whole yeast replicative lifecycle according to the researchers [52-56]. Microfluidics can sort yeast cells depending on a variety of parameters. Keinan et al.[58] used a technique that balanced shear-induced forces with other hydrodynamic forces within a curved channel to sort larger yeast. Young and adult populations of yeast were isolated by 107 cells/min/ channel rate from mixed populations. The technology is effective for high flow rates, preventing clogging and increasing throughput, and it can sort yeasts in the spirits sector [59]. Their method allows for large-scale separation of microbes based on minute size differences (±1.5 µm), which is unsurpassed by other technologies [60,61]. They discovered that expression of recognized yeast age markers can fluctuate far sooner than previously reported, after two to three budding events, utilizing this technique and a newly devised algorithm for evaluating bud scars [62]. According to mass spectrometry analysis of sorted yeast populations, the proteomic patterns of young and adult cell populations derived from the same colony varied considerably in terms of expression of youthful and aging markers. A microfluidic procedure was performed in another study to differentiate and separate genetically similar yeast strains dependent on adhesion strength [63]. Different yeast strains have different strengths which can distinguish them from a mixed cell population. They showed the technique's efficacy by measuring the differential adherence of nine commonly used S. cerevisiae laboratory variants and mutations lacking fungal adhesion-related FLO family genes. They determined that the solution's ionic strength

and the substrate's hydrophobicity influenced yeast adhesion. As illustrated in Figure 1B, Sesen et al. [57] presented a two-phase microfluidic system. The system is capable of real-time imaging within droplets during flow. Even though the process is based on droplet sorting, it is rather adaptable and hence has the potential for yeast sorting. The acquired digital images were processed to determine which cells should be sorted depending on programmable/ adjustable attributes. Sorting is done by the application of an electric field to induce a force called dielectrophoresis [64,65]. To demonstrate the system's capabilities, it is configured to handle the Poisson loading problem by filtering for droplets carrying a single 85 percent pure red blood cell. Additionally, utilizing fluorescence imaging and machine learning, single K562 cells were put into clusters depending on size and circularity. Yu et al. [66] demonstrated sorting yeast cells based on their morphological characteristics using this image processing technique, as previously indicated. Because pictures take longer to gather and analyze, the detection rate is quite slow (12 cells/minute). Microbiological contamination detection is crucial for quality control in the brewing industry, as it can result in significant recalls and impairment to the brand's reputation. Condina et al. [67] proposed a novel, low-cost strategy for the high-throughput and useful separation of yeasts (S. cerevisiae and S. pastorianus) from beer spoilage bacteria (Lactobacillus brevis and Pediococcus damnosus) using inertial microfluidics and flow separation in a spiral microchannel. They exhibited high-throughput, rapid separation of spoilage bacteria of size 0.3–3 μm from background yeast of around 5 μm with an efficiency of 90 percent. This system could be linked into the manufacturing process, enabling real-time assessment of beer spoilage and rapid response to contaminant breakouts in the brewery. Other than yeasts, different factors are important to be considered for the fermentation process monitoring. Microfluidics along with different sensors can do measurement of various components in fermentation, such as ethanol, potassium, carbon dioxide, acetoin. An overview of those is shown in Table 1. One study combined microfluidics with potentiometric detection for monitoring total potassium in winemaking operations without sample preparation [68] with a good limit of detection (LOD), reproducibility, and repeatability (Table 1). These characteristics make it ideal for ongoing monitoring of total potassium levels in wineries, particularly throughout critical stages of the fermentation process such as grape cultivation/reception, fermentation, and final product quality standards. As the system does not need any sample pretreatment, this automated system has at least four months lifetime for repetitive analysis. Applying

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LIMIT OF DETECTION

REFERENCE

75 ± 12 mgL-1K-1

[68]

83 mgL-1

[69]

10-100 µM

[70]

0.105 µM

[71]

TABLE 1 Fermentation process parameter monitoring using microfluidics. DETECTED COMPONENT

DETECTION METHOD

Potassium

Microfluidics with potentiometric detection Microfluidics, gas diffusion module along with optical flow cell Sensor with enzyme acetoin reductase

Carbon dioxide Acetoin/Diacetyl Hexoses (glucose & fructose)

Electrochemical sensors

Ethanol concentration

Microfluidic membrane device

Microfluidics with pH sensing membrane

a pH-sensitive acceptor solvent, the same group proposed a low-cost cyclic olefin copolymer-based microsystem with an integrated gas diffusion step for spectrophotometric CO2 detection in wines and brews [69]. The technique applied to the real samples and hydrodynamic variables with a range from 255 to 10,000 mg/L of CO2 and a LOD of 83 mg/L with a sampling rate of 30 samples per hour. Another study described a capacitive electrolyte-insulator semiconductor field-effect biosensor for detecting acetoin [70]. The sensor can monitor the pH change because of the enzymatic dehydrogenase. The detection concentration range of acetoin is between 10 µM and 100 µM, measured in a buffer solution of pH 7.1. López-Fernández et al. investigated the potential of thin film electrodes made by the combination of copper-cobalt oxide compiled in a single step via vapor deposition and made a non-enzymatic electrochemical sensors for hexoses (glucose plus fructose), as well as the feasibility of using such a system for fermentation process monitoring [71]. Films with a Co/Cu atomic ratio of 3.4 had a sensitivity 0.710 A/M-cm2, a small LOD of 0.105 μM, and remained stable at long storage periods, according to this study. The capabilities of this electrocatalytic sensor were examined for synthetic wine fermentation process, with promising results for in situ monitoring. Lu et al. [73] developed a pH detection device based on a microfluidic chip that can measure pH levels in extreme acidic and alkaline situations in real time. A pH sensor membrane, as well as a light source and photodiode, were used along with a microfluidic chamber to create the sensing chip. The amount of light that was transmitted changed as the pH of the fluid changed. The designed pH sensing chip has a response time of 90 seconds and works in the pH ranges of pH 3.0 (5 M [H+]) to pH 6.0 (2 M [OH-]), making it suitable for on-line monitoring. Lopes et al. [74] developed and validated a 3D printed millireactor with passages loaded with yeast trapped in THE JOURNAL OF DISTILLING SCIENCE

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13.0 vol% at 25 °C and 7.8 vol% at 30 °C 5 M [H+]-pH 3.0 and pH 6.0-2 M [OH-]

[72] [73]

alginate hydrogel for alcoholic fermentation. The best millireactor configuration was a 2% of alginate solution with 25 g/L cells, which produced 11.24± 0.015 g/L of ethanol on average, with a productivity of 22.49 g/L-h and a 44% efficiency. They've established that their technology and procedures are viable alternatives for fermentation, outperforming millireactors with free cells. Further, a technique for detecting or monitoring ethanol concentration during fermentation can influence production efficiency. By constructing a responsive microfluidic membrane device with a layered ethanol-sensitive barrier in a "stamp-like" manner, a novel approach of ethanol concentration was established for online monitoring [72]. The microfluidic membrane devices exhibit key interactive ethanol concentrations around 10% at temperatures below the volume phase transition temperature, e.g., 13.0% by volume at 25 °C and 7.8% by volume at 30 °C and could be connected to a practical ethanol production or separation system for ethanol concentration monitoring. The device possesses properties of reversibility, repeatability, high stability and long lifetime, which may benefit industry where monitoring a quick shift in pH benefits online pH detection systems. MATURATION

One of the crucial elements impacting distillation quality of the product is the transformation of lignin into non- or low-volatile phenolic compounds during maturation. The presence of atypical or abnormal amounts of these compounds may indicate that the aging was induced artificially or may indicate some type of adulteration [75]. As a result, profiling those lignin-derived phenolic chemicals that can signal aging as well as cask diversity in the maturation process is critical. High performance liquid chromatography (HPLC) was chosen as the best method for analyzing the low-volatility chemicals created throughout the aging 31

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process [76]. This approach has been used to measure low molecular weight phenolic chemicals in aged wine brandies, such as phenolic aldehydes and acids [77,78]. To identify both volatile and non-volatile chemicals created during spirit maturation, gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) have been used [79-81]. One of the key unsolved difficulties is identifying chemicals that are important in distinguishing spirits of different eras. To identify aged wine distillates and other spirits, the ability to evaluate non- or low-volatile phenolic compounds quickly and precisely is critical. Microfluidics, along with different sensing mechanisms, could be useful for quick and efficient identifications of aging markers. Microfluidics coupled with electrophoresis or other sensing methods can measure phenolic chemicals and assess the impact of aging. Among them, capillary electrophoresis (CE) is the most popular, defined as an electrokinetic separation technique that uses an electric field and a small capillary tube to separate molecules or ions [82]. Capillary electrophoresis is a well-established technique for regular examination of inorganic and organic ions, short-chain organic acids, carbohydrates, etc. [83-85]. In one study, four different phenolic aldehydes (syringaldehyde, sinapaldehyde, vanillin, and coniferaldehyde) and five distinct phenolic acids (ferulic, syringic, vanillic, p-courmaric, and p-hydroxybenzoic) were identified in aged brandy and wine and were separated using capillary zone electrophoresis [86] and a variable wavelength UV detector [87]. The total amount of such chemicals increased with age. The sum of syringic and vanillic acid concentrations can characterize products by their aging level. However, no consistent rise in aromatic acids has been detected in distillates older than 25 years. In whiskies, White et al. [88] employed a similar approach of capillary electrophoresis with UV detection. They looked at how the phenolic acid profile of three types of Irish whiskies was affected by aging length, aging process, and whiskey mashbill: different types of whisky from the same distillery, single malt whiskies matured in different casks within the same distillery, and a range of single pot still whiskies unique to Ireland. As with the previous study, aging had a beneficial effect on the levels of phenolic acids found in whiskies. In addition, the variety of phenolic acid compounds in the finished whiskeys was influenced by the casks used, with sherry casks having the most phenolic ingredients. To assess Scotch whisky age and barrel type, researchers used UV-Visible spectroscopy and low-powered ultrasonic characterization [89]. The variation in compressibility of the complete sample, which includes congeners in the maturing spirit, is assessed using the speed of sound, which can be used to identify the age of various samples

(Fig. 2A). UV-Visible spectroscopy was used to check the Scotch whisky cask type. Additionally, it was detected alternatively aged ones meaning the maturation was done unconventionally or reflect some form of adulteration [75] because they have different peaks with congener profiles. According to spectrophotometry, the antioxidant content in Scotch whiskies increase with age but may decrease with alcoholic strength. Although this study was not conducted on a microfluidic device, the underlying physics can be adapted to that scale; for example, acoustic microfluidic devices [90] have been used to manipulate and characterize samples. Wei et al. [91] used a convenient electronic nose (E-nose) with a sensor comprised of an array of 12 "metal oxide sensors" to recognize rice wines of various ages. The sensor chamber had an inlet and an outlet, and a sample was poured in through the inlet. The wines' VOCs were then detected by circulating in a closed loop channel, as shown in Figure 2B. A wireless connection module was used to send the obtained response values to a smartphone. Sensors can detect ammonia, methane, butane, propane, trimethylamine, methyl mercaptan, and other volatile organic components, which can be utilized for categorization and prediction analysis. To categorize data, various data processing algorithms were utilized, including principal components analysis (PCA), locally linear embedding (LLE), and linear discriminant analysis (LDA) [94-96]. To anticipate different marked ages of the wines, partial least squares regression (PLSR) and support vector machine (SVM) were applied as machine learning algorithms [97,98]. With a greater correlation (R2 = 0.9942) and a smaller root-meansquare error (RMSE = 0.0404), the SVM approach provided the maximum accuracy of the taste set of rice wine samples. They conducted the tasting at the lab's constant temperature, ignoring the temperature fluctuation impact that is essential for wine factory testing. Overall, because of its tiny size and portability, it is a workable solution that should be examined further. Gustatory and olfactory sensor systems were built and utilized to categorize vinegar samples with varied indicated ages in another study [99]. They combined two sensor systems to cover a wider range of chemicals than a single sensor system could. With the use of PCA and LDA, the signal of sensor arrays was changed as the VOCs in vinegar varied during storage. In this study, the PCA and LDA both have a high classification rate of vinegar (up to 100%), leaving the possibility of identifying wine and other spirits with varied marked ages. In a different experiment, Prat-Garca et al. [100] proposed a method for detecting the distribution of O2 content and its changes throughout the interface and adjacent liquid of oak wood pieces soaked in a model wine by employing

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(A)

(B)

(C)

(D)

FIGURE 2 (A) Speed of sound and compressibility variation for whisky with age (Sample ID 16, 18, 21). Different value for distinctive ages. Reprinted with permission from [89] (Copyright 2020 John Wiley and Sons) (B) The setup of the system showing the sensor chamber. Adapted with permission under a Creative Commons Attribution-NonCommercial 4.0 International License from [91] (https://doi.org/10.3390/s17112500). (C) Detailed illustration of the microfluidics chip. (i) Chips for generating droplets (ii) Droplet storage for incubation process (iii) ChipMERGE for merging the droplets (iv) ChipDET for measuring concentration. Reprinted with permission under a Creative Commons AttributionNonCommercial 4.0 International License from [92] (https://doi.org/10.3390/mi6101435). (D) Methanol detection using capillary electrophoresis coupled with conductivity detection. Reprinted with permission from [93] (Copyright 2017 American Chemical Society)

O2 responsive nanoparticles and an RGB camera. With a constant oxygen content in the nanoparticle solution, the system was calibrated. The oxygen optode probe device may then monitor the variation in the model wine once the oak wood is inserted in the measuring cell. The kinetics of oxygen transfer-consumption in a wood soaked in a model wine were depicted by altering the exposure period in both the regions adjacent to the wood and the liquid itself. Furthermore, because to the high resolution of the digital images, the differential release of O2 from distinct parts of the wood could be seen. The slow and continuous diffusion of oxygen from wood piece occurs and sustains the processes involved with wine aging, and this research aids in visualizing the dynamic behavior of wood degassing and oxygen absorption. Thus, this system could compare the THE JOURNAL OF DISTILLING SCIENCE

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behaviors of different areas in the same wood sample, enabling a straightforward method of analyzing the complex interaction of spirits with oak. DRINK IDENTIFICATION & AUTHENTICATION

Because rebranding low-quality commercial whiskeys as premium products may be extremely damaging to a producer, maintaining the safety and quality of alcoholic beverages is a constant concern. Chemical analysis has been used to evaluate and authenticate the quality of food and beverages. Contaminated and/or fraudulent items will have a considerably different composition [101,102].

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Ethanol concentration

categories of alcoholic drinks with ethanol concentrations ranging from 5% v/v for beer to 53 percent v/v for scotch whiskey. Churski et al. [92] demonstrated a microfluidic platform for determining the concentration of ethanol in micro-droplets (Fig. 2C). In comparison to previous tests, the microdroplet approach delivers good reproducibility with a relative error less than five percent, high selectivity for ethanol, low reagent usage, and a wide range of 1–70 g/L. They demonstrated that the reliance of ethanol production on glucose content can be used to screen fermentation conditions and alcoholic beverage quality using high-throughput microfluidic technologies. The amount of sample required for each experiment can be greatly reduced by incorporating the well-known enzymatic assay for ethanol detection into the micro-droplet format. This enables high-throughput screening and extends the range of ethanol concentrations that can be detected. These benefits render the system appropriate for fermentation research in the industry for ethanol concentration at various production stages. For quality monitoring of single malt Scotch whisky, Ashok et al. [108] proposed using near infrared spectroscopy on a fiber-based optofluidic device. They showed that Raman spectra may be used to predict the alcohol level of a beverage to within one percent prediction error. In addition, principal component analysis (PCA) was used to classify whiskies depending on their age, kind, and cask. The findings indicate that this optofluidic probe is ideally suited for developing portable devices for alcoholic beverage authentication. Sensors have an important role in determining the quality of drinks, particularly ethanol and other alcohols. For example, Da Silva et al. [106] have described a method for quick on-line ethanol content assessment using a terahertz sensor and a microfluidic platform. The absorption coefficient of liquid altered as permittivity varied due to varying ethanol concentration. The transmission signal from which they detected ethanol content rose or declined as a result

Primary alcohol (ethanol) determination is a significant characteristic in the fermentation industry, determining not only product yield and quality, but also its potential value. For a variety of reasons, including statutory labeling of ethanol content for tax purposes, local government-imposed public policy, and even religious considerations, precise and accurate measurements of ethanol is essential to preserve the quality and features expected by customers. Microfluidics along with other separation and detection technique such as capillary electrophoresis and UV light can be used for quantification of alcohols in drinks. Table 2 summarizes this information. Rezende et al. [103] announced for the first time the implementation of a method for quantifying the alcoholic percentage in whiskey samples using micellar electrokinetic chromatography (MEKC) [104] on microchips in combination with the contactless conduction detection method. Ethanol, butanol, and pentanol were all separated using this approach. The alcoholic content of confiscated whiskey samples was assessed and compared to previously authorized samples with a 95 percent confidence level. The devised method has a fast analysis time which is less than 180 seconds, linear behavior in the range of 1.0 to 25% alcohol by volume with R2 = 0.98, and a LOD of 0.5% ethanol by volume. The methodology described herein may be a straightforward and effective microchip strategy for quality control as well as a quick tool for determining the authenticity of whiskey samples. Such an inexpensive authenticity system may be valuable for the consumer. In another study, Cordeiro et al. [105] presented a rapid, simple, yet reliable method for determining the ethanol content of various liquors depending on oxidation reaction with the use of a UV-LED/H2O2 system as a solvent extraction step before to CE with the UV detector. In terms of ethanol, the LOD was 50 μmol/L. The proposed method was successfully applied to the analysis of 12 distinct

TABLE 2 Quantifying of ethanol using microfluidics. DETECTION METHOD

Micellar electrokinetic chromatography (MEKC) on microchips Photochemical oxidation under UV-LED irradiation Droplet microfluidics with enzymatic assay

LIMIT OF DETECTION

WORKING RANGE

REFERENCE

0.5% (v/v) for ethanol

between 1.0 and 25% (v/v)

[103]

50 μmol/L for ethanol

between 5% v/v to 53% v/v

[105]

70 g/L

1-70 g/L between 9.35% and 70.80% of ethanol

[92]

Microfluidic devices and Gigahertz sensor

–

Microfluidic bioassay with hydrogel sensing elements

70 µM of alcohol

–

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of this alteration. They identified equivalent quantities between 9.35% to 70.80% in a concept-proof for water-alcohol combinations. This device could be used in the drinks and chemical industries to perform in-line concentration measurement and control on small samples with a low error of 0.32 percent between measured and original concentration. Jang et al. [107] developed microfluidic devices with strips of hydrogel sensing microstructures that entrap quantum dot (QD)–enzyme conjugates for simultaneous glucose and alcohol detection. The model enzymes were glucose and alcohol oxidase, which were coupled to carboxyl ended CdSe/ZnS QDs and confined inside the hydrogel spherules, resulting in a fluorescent hydrogel grid that was glucose or alcohol-responsive. Based on the response, the quantity was determined. This systems' LOD were discovered to be 50 µM and 70 µM for glucose and alcohol, respectively. Because their innovative microfluidic system included many microchannels, they were able to detect glucose and alcohol simultaneously, and each micro-channel could run various assays independently, which could be useful for beverage quality monitoring. Ethanol biosensors have recently played an important part in the quality determination of alcohols, where enzymatic processes are used to detect and quantify ethanol. Alcohol dehydrogenase, alcohol oxidase, and microbes are the three basic bio-components employed in biosensors [109-111]. Ethanol biosensors operate over a wide range of values with typically a linear correlation between ethanol concentration and measured signals. They have a low LOD of 0.1 µM and a fast detection time (seconds to minutes) [112]. Methanol concentration

While preserving the alcohol concentration, it is also critical to guarantee that the liquor contains no hazardous compounds. Methanol (methyl alcohol) is of particular significance since it can be toxic at high concentrations, causing blindness and even death [113,114]. The maximum concentration allowed by the US Food and Drug Administration and the European Union in distilled spirits is normally 0.35% to 0.5% (depending on the spirit) [113,115]. As a result, microfluidic technologies enable the development of cost-effective, portable devices for quick methanol detection. In one study, Wang et al. [116] introduced a methanol detection microfluidic distillation chip that includes a serpentine channel. It also has boiling and heating zones, and the cooled product was collected in deionized water. The serpentine channel is used to transport the ethanol-methanol-water mix. Then, using a nitrogen carrier gas, it was collected in a chamber where it condensed in water. The combined indication and the methanol concentration THE JOURNAL OF DISTILLING SCIENCE

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obtained by spectrophotometer absorbance measurements react with the condensate, which also contains nitrogen. It has a distillation efficiency of 97.9 percent and can detect methanol concentrations between 300 and 800 ppm. Another paper describes the first time that electrochemical derivatization was combined with a hybrid CE platform [117,118] and capacitively coupled contactless conductivity detection to monitor methanol and ethanol concentrations during the distillation process to ensure the quality of the liquor [93] (Fig. 2D). This method can measure both methanol and ethanol simultaneously, with a LOD of 20 and 50 µmol/L for ethanol and methanol, respectively. Based on Waveguide Confined Raman Spectroscopy, another analysis revealed an optofluidic sensor for predicting both the methanol concentration (toxicity) and the ethanol concentration (quality) with 0.1 and 0.7 percent accuracy by volume using a Partial Least Squares-based chemometric model [119]. This sensor was used to analyze two vodka samples and one whiskey sample, and the model was able to clearly distinguish harmful beverages. Each model has its portability, low power requirements, and small sample quantities. The suggested approaches can be used not only in the lab but also in the field and even as an in-line monitor for distilleries. Drop drying

We can investigate the pattern creation left by drying droplets as a simple technique of identification and classification of beverages. The suspended micro- and nanoparticles in liquids form monolayers and/or are gradually deposited during the evaporation process resulting in the formation of diverse structures. Indeed, the formation of complicated systems from a droplet of colloidal suspension on a flat plane is a well-established phenomenon that has been utilized to describe blood serum, proteins, bacteria, DNA suspensions, and organic compounds, among other things [120-124]. Similar approaches can identify and analyze spirits. Some studies were conducted based on drying droplet by evaporation to identify and classify drinks. For example, González-Gutiérrez et al. [125] reported an approach based on crystallization patterns formed during the evaporation of alcohol droplets. They discovered that adding salt to the drying process enhances the gathering of crystals around the colloids, but that there were no apparent patterns in pure samples as shown in Figure 3A. They found that tequila patterns are easily repeatable. They identified that when different sample droplets were dried, they form a different pattern of structures that can be distinguished by density profiles and concluded that the method can distinguish between pure and contaminated drinks. In another work, Carrithers et al. [126] revealed that when a drop of 35

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Volatile Organic Compounds (VOCs)

American whiskey was evaporated, a self-assembled pattern arose and deposited on a surface to form hierarchical weblike patterns that they dubbed it a "whiskey web" [127]. The resulting pattern can be utilized as a liquid's chemical fingerprint, which not only distinguishes each item but also explains the distinct pattern of deposits from drying droplets for each substance (Fig. 3B). Yakhno et al.[128] recently proposed a novel method for deciding the similarity/difference between spirits without measuring their constituents, due to a high responsiveness of the oscillatory sensor's electrical behavior to the dynamics of a drop of the sample drying on the surface. Each liquid generates its own types of imprint, which is represented by the geometry of the amplitude curve or the difference index in the proximity of the hodographs (Fig. 3C). The scientists claim that despite the fact that droplets of drinks must evaporate under normal room settings, the dynamic "fingerprint" might replace the regularly used barcode and form a basis for wine product authentication.

The chemical composition of alcoholic products is extremely complicated, with 300-1500 distinct chemicals found in various liquors [5,10,11]. Fermentation, aging, and storage produce aldehydes and ketones, which contribute significantly to the characteristic aroma of alcoholic beverages. Drinks have a diverse aroma because of these VOCs. Because it is predicted that adulterated and/ or faked items will have a considerably different chemical composition than authentic samples, determining chemical indicators in alcoholic beverage samples can be used to investigate the process of certifying the drink's quality and authenticity [101,102]. Studies that were previously discussed in the Maturation section can be applied to this section to identify different liquors. In addition, there are some studies in literature that can identify the drinks based on different VOCs. Heller et al. [129] used CE to establish a quick analytical method for determining the aromatic aldehydes namely, coniferaldehyde, sinapaldehyde, vanillin, and syringaldehyde in

(A)

(B)

(C) FIGURE 3 (A) The effect of diluting on the deposited whiskey patterns. The creation of webs in different ages of whisky: (a) 3 years old, (b) 23 years old. Reprinted with permission under a Creative Commons Attribution-NonCommercial 4.0 International License from [126] (https://doi. org/10.1103/APS.DFD.2018.GFM.P0002) (B) Aggregation pattern observed in Tequila sample as a function of NaCl concentration. Reprinted with permission from [125] (Copyright 2017 AIP Publishing) (C) Hodographs of liquids of various types in a variety of shapes: Dry red wine is number 1; cognac is number 2; whiskey is number 3; balm is number 4; and vodka is number 5. Reprinted with permission under a Creative Commons Attribution-NonCommercial 4.0 International License from [128] (https://doi.org/10.3390/s20185266) 36

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whiskey, as well as to monitor the concentration of these chemicals in real and seized samples suspected of being false. They investigated 32 different Scotch whiskey samples in the study, and they separated authentic samples from questionable ones in under a minute. The analysis of such chemicals in whisky samples can help learn more about the procedures involved in whiskey manufacturing as well as to ensure the quality and authenticity of the beverage. In one study, a gas sensor made by metal oxide was incorporated into a digital microfluidic platform to identify VOCs in wine aromas via liquid sample analysis [130]. A hydrophobic porous microchannel mitigates the influence of the gas sensor's water cross-sensitivity, enabling the detection of wine aromas selectively. The transient responses of the device to diffused aromas from seven different wines, including three distinct types of shiraz, sauvignon blanc, cabernet, shiraz/cabernet blend, and syrah are recorded and compared along the channel in order to differentiate between different types of wine, as well as their producer and vintage years. To successfully apply the method, it is important to increase the selectivity range of the gas detector for different VOCs. The same author evaluated the effect of coating the channel and polarity of the analytes on the gas detection techniques of a microfluidic-based gas detector for this purpose [131]. When it comes to selecting the appropriate channel coating, the data indicate that non-polar coating surfaces exhibit more selectivity against non-polar gases, while polar gases are less affected. This can be utilized to create a set of micro-channels with different polarities to boost the device's separation power. Ghafarinia et al. [132] used microfluidic channels with a single

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gas sensor to differentiate eight alcohol vapors, including their isomers, based on their differing rates of diffusion and physisorption, to boost selectivity. Another way to accomplish the duties described is to use an electronic nose [133,134]. Zhang et al., for example, proposed the NOS.E, a new E-nose instrument with an auto-mated air intake design that was employed for standardization of odor detection and identification purposes [135]. Using the PCA pattern recognition technique, the sensor array can produce various VOC profiles that can classify and detect three different alcohol samples. It also includes a fault detection and alarming architecture, allowing it to deliver high-reliability results by constantly checking its operational state. While the proposed NOS.E (Sensitivity: 1ppm, Noise Level: 2–32mV) does not yet equal the capabilities of existing e-nose systems, it does provide end users with configurable odor evaluation platform that enables them to create their own sensor array. This and other similar microfluidic monitoring systems can rapidly detect if the spirit has been compromised and may aid in the identification of the source of contamination. Based on the differential pulse voltammetry technique's selected current component, Wójcik et al. [136] employed voltametric sensors to profile wine and Scotch whisky samples with a complicated composition using voltametric sensors. This novel technique has the potential to represent a significant step forward in the development of voltametric complicated sample profiling, as well as the fabrication of electronic tongues. A multi-sensor fusion system was developed in another study, based on a revolutionary cost-effective E-nose and a voltametric electronic tongue.

(A)

(B)

FIGURE 4 (A) Identification of different liquors based on the PCA score. Reprinted with permission from [139] (Copyright 2018 American Chemical Society) (B) (a) Schematic of microfluidic chip producing and merging droplets. (b) Close view of merging microdroplet cavity. Reprinted with permission under a Creative Commons Attribution-NonCommercial 4.0 International License from [140] (https://doi.org/10.1007/ s00216-018-1516-6) THE JOURNAL OF DISTILLING SCIENCE

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The system can successfully classify red wines with different brands, geographical origins, and grape varietals [137]. The results suggested that extreme learning machine models by PCA scores of E-noses and tongue as inputs have a strong potential for quick red wine quality evaluation. For more information about E-nose application, we would like to refer the reader to a review article by Sanaeifar et al. [138], where he discussed the application of E-noses in beverage analysis. In a separate study, Li et al. [139] proposed a colorimetric sensor array for the rapid and easy identification of liquors such as rye, scotch, vodka, bourbon, and brandy that utilizes multiple classes of chemo-responsive sensor inks such as pH indicators, redox indicators, acid/base indicators, specific aldehyde/ketone sensitive indicators, and solvatochromic dyes. The sensor, which is based on hierarchical cluster properties, PCA, and SVM analysis, accurately categorizes 14 liquors by their alcohol by volume and brand name, with a rate of >99% accuracy (Fig. 4A). Additionally, the sensor array is capable of detecting dilution (i.e., "watering") of distilled spirits with a water input of as little as 1%, highlighting its potential for quality control and assurance in the spirits industry. This handheld device can be used as means of portable quality control assessment, including confirming appropriate dilution. The colorimetric sensor systems arguably offer the greatest option for a low-cost, portable, yet sensitive way of assessing wine quality, especially given its capacity to account for large amounts of chemical information on the flavor constituents. However, because colorimetric sensor arrays use a visible spectrum of light (RGB, with wavelengths spanning from 0.4 to 0.75 mm), the extremely minute particles in wines scatter at their highest under the Mie scatter reign [141], deteriorating the performance of this sensor array. Because undiluted red wine runs over chromatographic paper, particulate matter is removed from the red wine, paper microfluidics can be used as an expendable and low-cost replacement to calorimetric sensor arrays. Park et al. [142] devised and built a system to assess ten distinct red wines and distinguish them from one another using a set of chemical dyes. The photos were taken with a smartphone's digital camera, and the red-green-blue color intensities were evaluated using PCA to differentiate each sample. The image processing and PCA approach might be turned into a standalone smartphone app for evaluating red wine and other beverage goods. In this section, we'll show research that doesn't fit into any of the previously mentioned categories. For example, Reid et al. [143] explored different methods for confirming food authenticity and quality, and they might be employed

in a microfluidic regime to identify and quantify specific components. Our discussion will be limited to the microfluidics regime, where other components, such as sulfite, sulfate, histamine, and others, have been found and quantified. Rovio et al.[144] used capillary electrophoresis to identify organic acids, inorganic cations and anions, and carbohydrates, as well as spectrum analysis, which determine chemical distinctions between six red wine samples from various locales. The pinot noir grape was utilized as a common nominator, and sensory assessment was performed to identify distinctions between wines. To monitor inorganic anions, Freitas et al. [145] employed environmental samples Cl-, NO3-, SO42-, and NO2- electrophoretic separations were successful, with LODs ranging from 2.0 to 4.9 µmol/L. The proposed analytical methodology can be utilized for routine environmental analysis and may be useful for the analysis of various ions in spirit, based on the results presented here. Rezende et al. [146] compared the concentration of those ions to that of original samples to authenticate seized whisky samples. They used microchip electrophoresis (ME) devices with contactless conductivity detection that was capacitively connected. ME devices differ from other microcapillary electrophoresis devices in that they provide quick analysis, low sample consumption and waste generation, high-throughput analysis capability, and compatibility with additional analytical stages on a single platform makes them suitable to be used in the industry [147-149]. The proposed microfluidic technology, according to the data, might aid regulatory authorities in the investigation and monitoring of the validity of commercialized whiskey beverages. Sulfite is commonly used as an antioxidant and antibacterial ingredient in beverages. On the other hand, it also has negative health effects in asthmatic patients, hence proper sulfite content assessment is critical to ensure the quality [150]. Vervoort et al. [140] created a reusable microdroplet technology (Fig. 4B) that can assess sulfite concentrations with a small sample of a fermented product with a LOD of 0.004 ppm and a three-orders-of-magnitude dynamic range. Although the tight array of micropillars prevents steady droplet reinjection, eliminating the pillars and combining miniaturized pumps and optics would allow this device to be used for high-throughput screening. While low levels of histamine in food are not regarded as a severe health danger, high doses can cause histamine poisoning [151]. As a result, determining the concentration in foods and beverages is an important consideration for maintaining quality. To overcome the issue, Stojanović et al. [152] suggested an electrochemical method for the voltametric measurement of histamine based on bulk-modified carbon paste electrodes with single-walled carbon nanotubes.

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It was acceptable for determining histamine levels in industrial beer and wine specimens since it had a low LOD of 1.26 μmol/L and a quantification limit of 3.78 μmol/L of histamine, as well as good reproducibility. The findings indicate that the suggested differential pulse voltammetry technique offers a potentially useful analytical tool for routine quality control of alcoholic beverages with reference to their histamine level. ADULTERATION/TOXIN DETERMINATION

Microfluidics analytical devices have already established themselves as a valuable tool as an alternative to traditional laboratory methods due to the ability for high-performance assessment in the food safety and quality industries. Biotoxins, foodborne pathogens, heavy metal ions, food allergies, and other chemicals present in food have all been determined using microfluidic devices [153-155]. However, the time-consuming sample preparation and detection techniques required by the varying complexity of a food matrix necessitates the incorporation of additional processing elements into the microfluidic chip, hence restricting the usefulness of microfluidics. Different spectroscopy approaches can be used with microfluidics to facilitate on-site analysis for different pollutants detection in food and beverages. Surface-enhanced Raman spectroscopy (SERS) techniques, for example, are becoming more widely used and accessible for the accurate and precise identification of chemical and microbiological contaminants in foods. Pu et al. [156] studied these approaches and their integration with microfluidics, concluding that they have tremendous potential for quick food contamination analysis. Additionally, the use of spectroscopy techniques combined with chemometrics enables for the quick and non-destructive examination, characterization, and identification of whisky fraud [157]. Combining NIR, MIR, and Raman spectroscopy with microfluidics, for example, can detect phony whisky and kindred beverages. Additionally, E-noses have emerged as a viable tool in a variety of fields of food safety evaluation for the speedy early detection of pollution and defects in the food supply chain [138]. It is associated not only with aroma profile but also for various contamination detection such as spoilage, mycotoxin. Spectroscopy can also be used with an electronic nose to detect flaws in beer and other beverages, which can be beneficial to small, medium, and large breweries. Viejo et al. [158] demonstrated a complicated approach for detecting flaws in beer that warrants additional investigation. Recently, various toxic components have sparked interest in screening in cases of alcohol adulteration. Urea, ochratoxin, scopolamine, and flunitrazepam are just a few examples. To guarantee that alcohol will be used safely, it is required to test potential contamination. Iida et al. [159] THE JOURNAL OF DISTILLING SCIENCE

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devised a method for determining urea in rice wine by combining microfluidics and an acid urease column-flow injection analysis system device, and the system was used in rice wine to determine urea. The proposed FIA system can determine urea in the range of 16 µM to 1 mM. Because the suggested method is not affected by ethanol or ammonia in samples, it can be used to determine many different types of amino acid oxygenase, decarboxylases, and amino-acid oxidase. Novo et al. [160] created a microfluidic enzyme-linked immunosorbent test device for detecting ochratoxin A(OTA) in different solutions more importantly in extracts of beer and wine. The LOD in pure phosphate buffered saline was 0.85 ng/mL using a straight channel arrangement for OTA. Even though the model was not validated with real samples, the system represents an important step for the creation of devices for OTA monitoring in the wine and beer industries. Jornet-Martínez et al. [161] created a Scopolamine sensor based on the entrapment of the reagent KMnO4 in PDMS, which is intended for quick Scopolamine analysis in beverages. The LOD is 108 µg/mL. A portable nano liquid chromatograph method was also developed, with a LOD of 100 µg/mL in this case. The proposed methodologies were tested on a variety of alcoholic and non-alcoholic beverages, demonstrating the viability of the two approaches for on-site testing. Tseliou et al. [162] created low-cost, electrochemical cells printed on a lab-on-a-screen for the direct, cathodic voltammetric detection of flunitrazepam in a variety of alcoholic and soft drinks. The system is ideal for a wide range of acidity (pH 2.3–8.4) and alcohol concentration (up to 40% alcohol by volume). The sensor's good performance for point-of-need screening of flunitrazepam to prevent covert drug administration is demonstrated by the data.

SUMMARY AND PERSPECTIVE To meet regulatory and consumer needs for spirits quality and safety control, the invention of cost-effective, portable, rapid, and extremely sensitive measuring instruments is necessary. Microfluidics devices continue to demonstrate their reliability and sensitivity to complement or replace established laboratory procedures due to their ability for high-performance assessment in the alcoholic beverages quality and safety sectors. In comparison to other disciplines such as clinical and environmental screening, contemporary microfluidics technologies for beverage analysis have been underused [155]. One challenge in its adoption is sample pretreatment, as it requires the integration of additional processing elements into the device, increasing the costs and complexity of the device. Specific testing aims may be efficiently achieved by utilizing physical properties to simplify sample preparation operations and by boosting 39

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microfluidic transport via microfluidic electrokinetics, inertial focusing, and other approaches. As a result, increased attention should be directed toward developing a variety of microfluidic platforms for real-time liquid sample analysis that include an integrated pretreatment process. Additionally, the described microfluidics or associated platforms typically target a single analyte and/or are limited in their analysis. But it may be necessary to develop systems that can be used for multiple analytes simultaneously. This review demonstrates the feasibility of in situ monitoring in the spirits business using a variety of approaches. A large number of integration opportunities for detection capabilities leads to more precise devices. The most frequently utilized chemical sensing methods include potentiometric, optical, chemical, and electrical detection [68,69,105,128]. Different sensing approaches in health sciences consequently increased the versatility of microfluidics in beverage analysis. For instance, a variety of detecting membranes are frequently utilized in beverage analysis [112]. Additionally, several electrokinetic separation techniques, like capillary electrophoresis, are the most adaptable for separating and quantifying chemicals in liquors and will continue to be used in microfluidic analytical systems. Recent advances in spectroscopic detection and machine learning have expanded the scope of this field [91,108]. Different machine learning algorithms can compare and predict different components at the same time using data from spectroscopic detections. This review demonstrated that the aforementioned methodologies have been successfully utilized to analyze various components — including ethanol [92], methanol [116], pH [73], and other VOCs [101] — in order to monitor the spirits' quality. Microfluidic technologies have also been used to identify some common contaminants or adulterations. Among these include urea, ochratoxin, scopolamine, and flunitrazepam. The findings indicate that several technologies have considerable potential for further research and commercialization in the spirits business. Emerging areas like turbidity, stability, foaming, color, etc. could be integrated with microfluidics for quality control. It can monitor variations in foaming stability regarding different properties of the liquors. For example, microfluidics can also determine viscosity [163] and how it can vary depending on the content of various components [164]. Even though current microfluidics studies have not focused on spirits, underlying fundamental microfluidics concept can determine how liquid properties change with changes in ethanol, amino acids, polyphenols, and so on. We can thus analyze fluid composition by investigating changes in viscosity, which can positively or negatively affect surface tension at the interface, and hence foaming stability. The identification of color consistency is another 40

thing that microfluidics could be used for. For example, the optical properties of spirit droplets can be analyzed for refractive index and color inconsistence[165] and could be applied to assess turbidity. In conclusion, this study discussed the significant advancements in microfluidics in the assessment of spirits over the recent years. The analysis and viewpoints presented in this study are believed to stimulate continued development of microfluidic devices in the spirits sector and other food safety testing and monitoring fields, benefiting human health and overall well-being. REFERENCES [1] McIntyre, A.; Bilyk, M.; Nordon, A.; Colquhoun, G.;

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A.; González-Miret, M. L.; Heredia, F. J.; Culshaw, B. Identifying the production region of single-malt Scotch whiskies using optical spectroscopy and pattern recognition techniques. Sensors and Actuators B: Chemical 2012, 171–172, 458–462. DOI: 10.1016/j.snb.2012.05.011.

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REVIEW

Blending Canadian Whisky – A Review Don Livermore1* 1 Hiram Walker & Sons Ltd., 2072 Riverside Dr. E., Windsor, Ontario, N8Y 4S5, Canada

KEYWORDS Canadian whisky blending whisky

RECEIVED: April 27, 2022 ACCEPTED: August 29, 2022 * CORRESPONDING AUTHOR: Don Livermore E-MAIL: don.livermore@pernod-ricard.com

Political events and technological advances caused the evolution of blending Canadian whisky. The American civil war naturally created an environment for Canadian whisky to become popular. The distilleries in the United States closed their facilities and the Canadian distillers took advantage of the situation. Canadian whisky production became quite profitable. This led to government control over the distilling industry, which required meticulous record keeping by excise officers. Canadian distillers took the opportunity to invest in their own infrastructure by adding tanks, bottling, and ageing facilities. These technological advances naturally lead to blending recipes. Blending was simple at first, combining a prescribed number of barrels as per formula, but through industry regulation and innovation blending evolved to become a very precise science that considers grains, fermentation parameters, distillation method, cask type, age, and strength of alcohol.

INTRODUCTION How does one learn to blend whisky? There is no specific school, training, or standard textbook that gives explicit instructions on how to make award winning whiskies. It traditionally has been a craft that has been handed down from one master blender to the next through storytelling. There is an art to understanding the combinations of flavours that work well together and when they become out of balance. It is about processing all the available information and putting it together to develop an exceptional blended whisky. A blender must understand consumer insights, inventory levels, costs, equipment capabilities, procurement, and the skill level of the human talents. A blender is central to whisky operations as the decisions made by

the blender steer the long-term future of the company. Canadian whisky did not intentionally start out as a blended style of whisky, nor does it have to be blended to be considered a Canadian whisky (Government of Canada 2022). As with many types of products, Canadian whisky evolved due to the circumstances that were happening in a specific era.

EVENTS THAT ADVANCED CANADIAN WHISKY BLENDING

In the early 1800s, rum was the choice of spirit for Canadians (Beaumont and Sismondo 2019). Canada was influenced by the British navy as it controlled much of the Caribbean territories which grew sugar cane. As the interior of Canada developed, settlers utilized local resources such as rye grain (Secale cereale) to make alcohol. Rye is capable of growing in the colder, harsher Canadian environment, and because of this, rye has become a staple of Canadian whisky blends today. However, most of the grain would have been imported TABLE 1 Original Mash Bills of Canadian Whisky Producers from the United States at that time because much of (Parliament of Canada 1898; De Kergommeaux 2017). the Canadian land was underdeveloped. Corn (Zea mays) would have been the PRODUCER YEAR CORN RYE BARLEY MALT OATS main imported grain from the United JP Wiser 1869 84 12 3 1 States. Many of the producers Hiram Walker 1883 78 17 5 — from that era would have used PRODUCER YEAR WHEAT WHEAT MIDDLINGS BARLEY MALT corn in a mixed-grain mash bill (Table 1). Gooderham & Worts 1830–40 10 83 7 48

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Very early whisky producers in at the time and a significant part FIGURE 1 Gooderham & Worts cooking and pot Canada would have sold a simple of the US culture. The war caused distillation system (Otto 1988). pot-distilled style of whisky in a existing distilleries to close as the ten-gallon cask (Figure 1). Basimen were required to fight in batcally, a consumer shows up to a tles and the metal from the distildistillery with a cask, and it would lation equipment was required for have been filled. The whisky was guns and ammunition, and the not aged for any length of time. grain and fruit were required for A typical operational size for a food. This left a need for a new Canadian distillery would not be whisky supply and the Canadian more than 20 casks a day. Disdistillers took advantage of the sittillers knew that consumers preuation (MacKinnon 2000). Addferred the lighter, smoother styles ing to the demand, whisky was of whisky and not the heavier, prescribed as a painkiller. The US full-flavoured, pot-distilled style government increased the tax revof whisky. General hygiene and enue on US whisky production cleaning were an afterthought as from $0.20 a gallon to $1.50 a galthe science of microbiology was lon over four years to finance the in its infancy. It was not underwar which created a financial instood how microbial infections centive for Canadian whisky (Edcreated undesirable off-odours wards 2015). which ended up in the whisky. Whisky was produced by the The 1860s were a great time for Canadian distillers. Inphase of the moon (Boruff and Wiener 1937), repeating the vestments were made back into whisky operations and same processes over and over without knowing why. advanced brewing and distilling technology. New copper The only way producers could achieve lighter styles of receiving tanks, distillation equipment, and fermenting veswhisky was to focus on methods of distillation. Various it- sels were added to increase capacity. The Canadian authorierations of stills were developed by Hiram Walker (Figure ties took notice and became highly involved in the distilling 2). The use of carbon filtration systems, rectification, and industry in order to control tax revenues and illicit distillamultiple trays improved the taste profile of the whisky by tion. Excise officers were assigned to each distillery to eneliminating off-odours. Precise operational control of the sure alcohol production was controlled. This forced the disstills was the way to produce a consistent light-flavoured tillers to document and record the entire business, because whisky. Distillers would market their products based on up to this point, production methodologies were passed their precise distillation skills. along through story telling from owner to son. Distillers Since whisky was sold by the cask, blending would have had to have a license, identify each piece of equipment, nobeen a limited activity as distillers would not have had the tify the government on the intent of trade, give notice when tank space or the technology operations started or stopped, to make complicated recipes record grain purchased, and the (Parliament of Canada 1898). amount of alcohol produced FIGURE 2 Hiram Walker three chamber charging still Records were not meticulously (MacKinnon 2000). By forcing 1870 (MacKinnon 2000). documented until the 1860s. Indistillers to make records, it crestinctively, blending could have ated the framework for blending. been done to cover up off-flaBy 1871, Canada was provours or to dilute batches, but ducing more than five million there are no records that remain gallons of whisky, of which today to suggest this was a formore than half the volume was malized practice. produced by Gooderham & The most significant historical Worts and Hiram Walker. The event that transformed blending world suffered a long deprespractices for Canadian whission through the 1870s which ky was the American Civil War caused metal and grain prices (1861–1865). Whisky was the to sharply decline and increased most popular drink in America competition between nations for THE JOURNAL OF DISTILLING SCIENCE

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alcohol production. Nations took advantage of low metal prices to build railroads and the distilleries that were located in close proximity to the spurs had the advantage of new routes to markets, while those who were not near railway access ceased operations (Archives of Ontario 1872). Canada went from more than 150 distillers to 19 in a period of ten years. Nations, including Canada, put in place tariff systems to protect domestic alcohol sales as a measure to retain tax revenues. The five largest taxpayers in Canada were the whisky distillers Gooderham & Worts, Hiram Walker, JP Wiser, Henry Corby, and Joseph Seagram. In 1878 the government imposed a form of prohibition at the municipal level, but it was only adopted for a brief time in twenty-five counties and two cities (Dawson 1895). The Canadian government’s control over the alcohol industry continued, and by 1883 the Inland Revenue Act was adopted into law. Whisky and alcohol production was manufactured under bond, meaning the excise duty on a bottle of alcohol was not paid until the bottle was sold. The production of whisky had to be in bonded buildings or other secured areas in which dutiable goods could be stored, manipulated, or undergo manufacturing operations without payment of duty. It could be managed by the government or by private business. In the latter case a customs bond had to be posted with the government. This quickly shifted industry from ten-gallon wood keg sales to bottle sales. Strip stamps were applied across the top of the bottle to ensure the contents of the bottle, indicate the date of manufacture, and that it was produced under supervision of the Canadian government. This formalized branding and marketing within the Canadian whisky industry and started the whisky blending era (Livermore 2021).

FORMALIZED BLENDING

would be 150 proof percent. The percent proof scale ranged from zero (100 UP) to 166.7 (66.7 OP) at 60 °F (His Majesty Customs and Excise 1938). Using the equation in Figure 3, the Imperial strength scale can be converted to percent ABV. If the strength is above 100 percent proof, use the overproof equation. If the strength is below, use the underproof equation. FIGURE 3 Conversion calculations for Imperial proof scale to abv.

Over Proof: (100 + OP) × 0.5706 = % abv Under Proof: (100 – UP) 0.5706 = % abv For example, if the value of 25 UP was recorded in 1886, it can be converted to 42.8% ABV. Likewise, 20 UP would be 45.6% ABV, and 50 OP would be 85.6% ABV. The Imperial proof scale was used by Canadian blenders into the mid-1950s as a means of reporting strength of alcohol (Livermore 2021). Non-whisky blending components were used in the 1886 Canadian whisky recipes (Hiram Walker Archives 1886). A black tea concentrate and a sugar syrup were the main two flavouring components (figure 4 and 5). The sugar syrup was mixed with boiling water to get it as thick as possible. It was cooled prior to use in recipes. The black tea was steeped in 25 UP whisky for 72 hours prior to use. FIGURE 4 Sugar syrup recipe 1886. SYRUP COMPONENT

Granulated white sugar

VOLUME (GALLONS)

1000 lbs

water

Definitions and regulations for whisky production evolved over time. The very first recipes were designed around the processes that were being used at the time which were very different from today’s formulations. The oldest recipe book in the Hiram Walker archives is from 1886. Mash bills were used, and fermentations were set at 78 °F, much lower than modern temperatures of 90 °F. Fermentations finished at approximately 5% abv. It was distilled into a base whisky that was proofed on the Imperial proof strength (PS) scale, which is not the same as the standard US proofing system today. The proof scale system is based on over-proof (OP) and under-proof (UP) which is centered around 57.06% ABV which was known as the proof line or 100 percent proof strength. To determine the proof strength percent, it is 100 plus the over-proof percentage or minus the under-proof percentage. For example, the value of 25 UP would be 75 proof percent and 50 OP

Today the use of syrup or a black tea extract is not allowed in Canadian whisky, but at the time it would have been a novel concept that may have given Hiram Walker a competitive edge. If either of those components were used in today’s recipes the spirit would be classified as a liquor or liqueur, depending on use (Government of Canada 2022). The other ingredient of note that was used in 1886 was caramel colouring. Many of the whiskies added caramel to

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FIGURE 5 Black tea recipe 1886. TEA COMPONENT

VOLUME (GALLONS)

Black Tea

215 lbs

PS 25 UP

8000

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the recipe to make the liquid appear darker. Caramel colouring has been a component to Canadian whisky from the very beginning and is not a new concept. It is only speculation, but it was probably added for the same reasons as it is today, to maintain consistency from blend to blend and to give a perceived premium quality. This would have been cutting-edge technology for the time period.

AGEING LAW The Canadian government realized the importance of whisky to the economy and the overall financial stability of the government and became fearful from competition of other spirits from around the world. In order to protect the Canadian whisky category, the government implemented a two-year minimum age requirement for whisky in 1890 (today the Canadian whisky minimum age is three years). It was felt that ageing increased the value and image of Canadian whisky (Cloutier 1890). They also placed high tariffs on imported spirits in order to make Canadian whisky more affordable to the Canadian consumer. Canada was the first country in the world to mandate a minimum ageing requirement for whisky. Such a condition applied twenty-five years ahead of the general mandates of the UK’s Immature Spirits (Restriction) Act of 1915, and seventeen years ahead of the US Taft Act in 1907). The UK was not aligned to ageing whisky at this time as it was thought it would prevent commerce and trade. It made Canadian whisky unique internationally. Canadian distiller George Gooderham was quoted, “there is probably no place in the world where purer or more wholesome liquors can be obtained than in Canada.” However, there was strong opposition amongst Canadian distillers to the law as Franklin Walker (owner of the Hiram Walker distillery) argued, “The government made the lion’s share without making any capital investment” (Dawson 1895). Distillers had to increase barrel inventory, build warehouses, and increase tank capacity to handle all the liquid. This was adding capital for the same amount of whisky business. Because of the ageing requirement, it was the first time that distillers lost spirit in the cask over the two-year period. It was calculated that the government gained duty on evaporative losses, and it had to be reconciled. Perhaps this was the first time the angel’s share within the whisky industry was documented. By the year 1900, Canadian whisky was the largest whisky category in the world. At that time Hiram Walker had six basic recipes that were being made (Hiram Walker Archives 1886). It was not clear which brands the recipes were intended for, but each had its own unique formulation (Figure 6). Formulas were calculated on total volume, which in this case was imperial gallons. Recipe design started with a base whisky of various proof strengths (PS) ranging from 25 UP to 50 OP. Interestingly, 50 OP would have been close to cask strength. Additional flavouring components were added to the base whisky to give a unique sensory profile. The recipes had interesting nuances; some had different spirit types such as rum or Scotch. Others had high wines (unaged whisky), plus the tea extract, sugar syrup, and caramel colouring. OF is an unknown component that was used in one blend. Caramel colouring was added and quantified by the naked eye. Instrumentation was not available to measure the hue of whisky in the 1890s. The Old Rye 25 UP whisky was the most produced whisky for Hiram THE JOURNAL OF DISTILLING SCIENCE

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FIGURE 6 The original Hiram Walker blending recipes. OLD RYE — 25 UP COMPONENT

VOLUME (GALLONS)

PS 25 UP

10000

Tea

Rum

Syrup

Coloring

12.5

OLD MALT — 25 UP COMPONENT

VOLUME (GALLONS)

PS 25 UP

8000

Scotch Full Strength

160

Syrup

High Wines

Rum

FAMILY PROOF — 20 UP COMPONENT

VOLUME (GALLONS)

PS 20 UP

8000

High Wines 50 OP

160

Syrup

160

OLD BOURBON COMPONENT

VOLUME (GALLONS)

PS 20 UP

8000

High Wines 50 OP

640

Syrup

160

Coloring

OLD TODDY — 25 UP COMPONENT

VOLUME (GALLONS)

PS 25 UP

8000

Rum (Full Strength)

160

High Wines 50 OP

Syrup

Tea

Coloring

2.5

RYE — 50 OP COMPONENT

VOLUME (GALLONS)

PS 50 OP

400

Rum (Full Strength)

0.25

Syrup

0.8

Tea

0.16

Coloring

0.25 51

Blending Canadian Whisky – A Review

Livermore

Walker in the 1890s, and the brand still exists today as Hiram Walker Special Old Rye. As an estimation, most of the recipes flavour profile would be a light, smooth style of whisky with a hint of rye — which is traditional for Canadian whisky.

POST PROHIBITION ERA

FIGURE 7 Canadian whisky recipes from 1940s to 1980s. 1949

100% Add:

4-year Straight Imperial 1/2 of 1% Std. Paxarette Sherry on Proof 40 lbs. Prune Wine to every 6000 Proof Reduce to 24.7 UP Colour to 18.75 of Series #52 on Lovibond's Tintometer

Blending Canadian whisky blending advanced post-Prohibition and became more industrialized. Legislative bodies set standards for the Canadian whisky category. The tea extract and the sugar syrup were no longer permitted in blends to qualify as a Canadian whisky. Recipes from the 1940s onward did not use syrup or tea as blenders (Hiram Walker Archives 1944). The use of a mash bill for Hiram Walker also started to change post-Prohibition. Grains were processed separately as much as possible. Corn would have been fermented separately, aside from the required barley malt for starch conversion; however, by the 1970s, distilleries would have moved to the use of enzymes from fungal fermentations for starch conversion instead of using barley malt. Eventually distillers moved to the commercially purchased enzymes that are commonly used today. Likewise, rye was fermented with the use of rye malt and barley malt, but eventually malt was removed for the preferable enzymatic conversion because of improved yield, flavour profile, and ease of use. Mixed grain mash bills would have been made for the purpose of a whisky flavouring component. A mixed grain mash bill has a heavy character which makes it a good blending component. Producers internally called this a bourbon which was understood as a mixed grain mash bill even though bourbon was more formally defined and protected much later by the US government. The philosophy was to cook, ferment, distill, and age each grain separately and blend later (Livermore 2021). This is not required by law to be considered as a Canadian whisky, but this tends to be how most of the larger producers prefer to make whisky. It allows for flexibility for innovation and recipe design years later. If the grains were mixed together at the beginning, it becomes more difficult to change recipes later. Today corn, rye, wheat, barley, rye malt, and barley malt are types of grains that are processed separately. Recipes evolved post-Prohibition by changing from the addition of ingredients on a volume basis to a percentage basis (Hiram Walker Archives 1956). Most recipes started by blending together a base whisky to a 100 percent level. Base whisky was considered one of three types of whisky: double distilled (DD) light corn whisky that was processed through a beer still and rectifying column, a mixed grain mash bill (bourbon) process through a single beer still, or a pre-blended whisky (blended together prior to ageing) that

combined DD and a single beer distilled rye whisky. After the base was blended, additional blending components were added to give character to the blend. This was kept in line with Canadian whisky tradition, but it was restricted to no more than 10 percent of the blend. Ingredients like American whisky, Scotch malt, Paxarette sherry, prune wine, vermouth, rum, or brandy. These ingredients were referred to as blenders and had to be at least two years of age in a wood cask or a wine. The order of addition was

THE JOURNAL OF DISTILLING SCIENCE

1953

100% Add:

4-year Imperial 7% 4-year Star Special 1/2 of 1% Std. Paxarette Sherry on Proof 40 lbs. Prune Wine to every 6000 Proof Reduce to 23.9 UP Colour to 23.5 of Series #52 on Lovibond's Tintometer 1957

1.0% 2.0% 26.0% 15.0% 56.0% Add:

1936 Star Special 1936 Imperial 1946 Whisky “CW” 1946 Whisky “MR” 1947 Corby's “C” Whisky 2.5% 4-year Star Special 2.0% 1946 “DG” Whisky (Dillinger Bbn) US 1.0% 1946 “PB” Whisky (Plum Brandy) 1.0% 1948 Walkerville Malt 3.0% 1945 Whisky “C” US Redistilled 1951 3/4 of 1% Std. Paxarette Sherry on Proof 3/4 of 1% Prune Wine on Proof

1958

92.5% 3.2% 1.1% 3.2% Add:

3-year DD Whisky 3-year Star 5-year Walkerville Bourbon 3-year Star Special 6.0% 1950 Peoria American Whisky “PG” 1.5% Std. Paxarette Sherry on Proof 40 lbs. Prune Wine to every 6000 Proof 1.0% 1948 Walkerville Malt Reduce to 30.0 UP Colour to 46% Transmission on Colorimeter

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Blending Canadian Whisky – A Review

1968

FIGURE 8 Barrel entry strength of whisky 1912 – 1954.

100% Add:

4-year DD 4% 4-year Three Star Rye 2% 4-year Walkerville Bourbon 5% 1949 “C” Whisky (Corby) 1/2 of 1% Std. Paxarette Sherry on Proof 40 lbs. Prune Wine to every 6000 Proof Reduce to 30.0 UP Colour to 44% Transmission on Colorimeter

IMPERIAL

1979

81% 19% Add:

15-year DD 15-year “CB” FB Whisky 7% 2-year DD 1.5% Walkerville Bourbon Reduce to 30.0 UP Colour to 44% Transmission on Colorimeter using 490 mm wavelength 1989

86.29% 6-year DD (25% rechar casks, 75% non rechar) 9.55% 6-year Star Special 4.16% 6-year Star Add: 2.5% 2-year French Grape Brandy Reduce to 45.0% abv Colour to 185 Absorbance on a Spectrophotometer at 525 mm wavelength

important to recipe design as the lighter ingredients (base whisky) were always added first and the heavier flavoured blenders were added last. Recipe styles evolved through the 1940s to the 1980s (Hiram Walker Archives 1956). The use of different blenders changed, maybe because of the master Blender philosophy at the time, or because of ingredient availability, or simply changing consumer tastes (figure 7). Instrumentation started to be used for colour measurements. The details of whisky inventory became more of a concern in recipe design which started to include age, type of base whisky, distillation type, cask type, and grain type. It should be noted that star refers to a rye that has been beer distilled, star special is a rye that has been beer distilled and then pot distilled, and Imperial is a pre-blended base whisky. This was the internal language used by the Hiram Walker distillery. All the way to the 1970s the original proofing scale was used but switched to the more modern alcohol determination in the 1980s. Alcohol strength of the whisky which entered the cask was also a concern (figure 8). Evidence from the Hiram Walker archives shows that the master Blender was trying to optimize the flavour profile for a pre-blended whisky and a DD whisky (Hiram Walker Archives 1940). THE JOURNAL OF DISTILLING SCIENCE

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Winter 2022

1912 to July 1939

@ 22.0 UP

August 1939 to October 1944

@ 0.2 OP

October 1944 to October 1948

@ 3.2 UP

October 1948 to May 1951

@ 11.0 OP

May 1951 to May 31, 1954

@ 16.0 OP

New Strength Adopted June 1, 1954

@ 10.1 OP

DD SPIRITS

1929 to July 1948

@ 0.2 OP

July 1948 to May 1951

@ 10.1 OP & 11.3 OP

May 1951 to May 31, 1954

@ 16.3 OP

New Strength Adopted June 1, 1954

@ 11.0 OP

The range of alcohol for the barrel entry strength was from 44.5% ABV (22 UP) to 66.4% ABV (16.3 OP) over a 40-year period. Today the base whisky enters a barrel at 76% ABV and the rye flavouring whisky is at 58% ABV. The strength is adjusted with water prior to ageing as a DD whisky exits a still at 94% ABV, a beer distillation is 70% ABV, and a beer plus subsequent pot distillation is 80% ABV.

MODERN BLENDING In the 1990s, the recipe construction changed slightly to align with the regulations. Recipes are now blended on a 100 percent scale, not blending the base whisky to 100 percent followed by the addition of the 10 percent blenders. In order to maintain the tradition of blending in two-year-old other spirits and wine, it was calculated that these components could not exceed 9.09 percent of the blend. A strange value, but it has a rationale. Adding together 100 percent plus 10 percent it equals 110 percent. Dividing 10 percent by 110 percent it is 9.09 percent, hence it has now become part of the Canadian whisky regulation (Government of Canada 2022). These components have to follow tradition and be at least two-years of age or wine, and not neutral grain spirits. The design of whisky recipes changed to blend on a litre of absolute alcohol (LAA) instead of a classic percent volume scale (figure 9). The active and taxable ingredient in formulations is alcohol. Canadian whisky recipe design moved in the direction of LAA blending for ease of government reporting. A second reason to blend by this method is for product consistency. Whisky formulations were becoming more complicated as the number of factors that influence 53

Blending Canadian Whisky – A Review

Livermore

flavours needed to be considered FIGURE 9 A typical blending recipe for a 10 000 L batch. to maintain product consistency. Star = column distilled AB = Once used American Bourbon cask Most of the whisky industry recStar Special = column then pot distilled If there is no description to the barrel type, ognizes that the strength of alcothen it is a used Canadian Whiskey barrel DD = double column distilled hol in cask will change over time, (base whisky made of corn) but it also changes inconsistently. The same batch of whisky Blend 40.0% abv aged in a different location in TOTAL a warehouse, or in a different PERCENT LAA COMPONENT STRENGTH VOLUME WEIGHT barrel type may yield differing 63.91 LAA DD — 10 Year @ 70.2% abv 3641.6 L 3219.2 kg strengths when drained several 15.00 LAA DD AB — 11 Year @ 66.7% abv 899.6 L 802.9 kg years later. For example, a barrel 8.50 LAA Rye Star Special AB — 10 Year @ 55.0% abv 618.2 L 568.1 kg of whisky may start at 58% ABV 3.50 LAA Rye Star AB — 10 Year @ 57.2% abv 244.8 L 223.8 kg but, after ageing the same batch of whisky in a different barrel, 4.50 LAA Barley Malt Star Special AB — 4 Year @ 57.3% abv 314.1 L 287.1 kg may range several percentage 3.00 LAA Wheat Star NW — 6 Year @ 57.8% abv 207.6 L 189.5 kg points (52% – 56% ABV) and 1.00 LAA American Bourbon @48.2% abv 114.1 L 106.4 kg have a different volume of liq0.59 LAA Apera Wine (Paxarette sherry) @14.6% abv 161.6 L 158.1 kg uid in cask after the process is Water 3798.4 L 3798.4 kg complete because of evaporation losses. This may seem like a small difference but could have a Knowing the strength of the first ingredient, the total volmajor impact on the final flavour, especially when combinume of first ingredient can be calculated: ing heavy flavouring whiskies with light base whisky. The VOLUME OF FIRST INGREDIENT BLEND current trends of rare releases and small batches magnifies LAA OF FIRST INGREDIENT ÷ STRENGTH FIRST INGREDIENT the importance of blending consistency even further. 100 Each whisky in the blend is drained separately and = 2556.4 ÷ 70.2 checked for alcoholic strength. Depending on the blend100 er’s comfort level or tank availability, individual ingredients = 3641.6 L should pass a sensory panel. If it meets specification, the whisky is acceptable for blending. In the example of the When blending in very large batches, it is important to 10,000 liter whisky blend in Figure 9, the total LAA adds blend by weight, as blending by volume is influenced by the to 100. Once each ingredient’s LAA and strength is detertemperature of the whisky. Especially in a climate like Canmined, the volume can be calculated. ada the temperature of the whisky in the ageing warehouse First the total amount of the litres of alcohol in the 10,000 varies based on the season. Using predetermined density liter blend is calculated: tables, the weight can be determined (Government of Canada 1980). The first ingredient has a strength of alcohol of TOTAL ALCOHOL IN FINAL BLEND 70.2% ABV, with the corresponding density of 0.88400 L/ TOTAL VOL × FINAL STRENGTH kg. Calculating the weight: = 10000 × 40.0 100 = 4000 LAA

100

The total amount of LAA of the first ingredient (DD – 10 Year) is calculated: LAA OF FIRST INGREDIENT IN BLEND TOTAL LAA × INGREDIENT LAA 100 = 4000 × 63.91 100 = 2556.4 LAA 54

WEIGHT OF COMPONENT TOTAL VOLUME OF COMPONENT X DENSITY OF ALC STRENGTH

= 3641.6 × 0.88400 = 3219.2 kg

Following the same calculations as the first ingredient, the remaining components can be determined. The second-to-last ingredient that is added is reverse osmosis water. It should be added slowly and as sparingly as possible. For commercial sized blending, it is easier to adjust the strength of alcohol by adding water than by adding more alcohol. If the strength drops below the final strength THE JOURNAL OF DISTILLING SCIENCE

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Blending Canadian Whisky – A Review

specification, then each ingredient will need to be added again in the exact proportion as the recipe prescribes. The tolerance of alcohol strength in Canada is plus or minus 0.3% ABV. The last ingredient to be added is caramel colouring. Usually, the required caramel that is added is in the ppm range, therefore changing the alcoholic strength is not a concern.

Beaumont, S.; Sismondo, C. Canadian Spirits. The Essential Cross-Country Guide to Distilleries, Their Spirits, and Where to Imbibe Them. Nimbus Publishing. 2019, 1-18. Boruff, C.S.; Weiner L.P. Technology Transcends Heritage in Modern Distillery Practice. Chemical and Metallurgic Engineering 1937, 44 (4), 182-185. Cloutier, E. Debates. House of Commons. Dominion of Canada. Fourth Session – Sixth Parliament. 1890. Vol. 30, 3729-3732. Dawson, S.E. Canadian Commission on Liquor Traffic, Minutes of Evidence Ontario. 1895, Vol. 4. Parts 1 & 2.

CONCLUSION How to blend, or at least the mathematical theory of blending, is the easy part. The precision has advanced over a century with the improvements in technology which have enabled the blenders to mix together many different types of ingredients. What to blend,is the difficult part. A master Blender must have a keen understanding of the origin of flavours and how the flavours are manipulated in the whisky making process. Tools are available such as The Canadian Whisky Flavour WheelTM, which explains the three prime areas (grain, fermentation, and casks) where a blender can draw in flavours (Livermore 2017). The blender must also understand the marketing side of the business and determine the purpose of the whisky when designing the recipe. A project brief from marketing could include a one-time rare release that targets uisgephiles (whisky lovers) or connoisseurs, or the brief may ask that a whisky strategically be designed for cocktails, or the whisky could be for new consumers to the category. Each type of whisky would be very different. It is also important to understand the competition, costs, and inventory levels. A master Blender must understand the equipment which manipulates whisky such as fermentation vessels, distillation units, condensers, and filtration units. One must understand the history of the distillery and be able to anticipate what may go wrong. Whisky can be prone to hazing or flocking which leads to product failure. It is up to the master Blender to be the keeper of history of all the information for the brand, distillery, and product design and must be able to determine the flavours that work well together and the flavours that clash. This can only be learned through experience and the best master Blenders will seamlessly teach their knowledge to the next generation by being a great storyteller. For further information on the details of flavour development in whisky — The Canadian Whisky Master Class Volume 1 “The Keeper of History” and Volume 2 “Blending 101” (Livermore 2021). Accessed at jpwiserstour.ca REFERENCES

Archives of Ontario. 1872. Canadian Manufacturers – No IV, One of the Largest Distilleries in the World. The Globe. Toronto. N11. R67. April 23, 1872: 2. THE JOURNAL OF DISTILLING SCIENCE

Livermore

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Winter 2022

De Kergommeaux, D. Canadian Whisky: The New Portable Expert. Second Edition. 2017, “Chapter 12: Gooderham and Worts.” Edwards, P. The Horrific Spike in Whiskey Prices During the Civil War in One Chart. 2015. https://www.vox. com/2015/8/7/9111123/whiskey-civil-war-chart [Accessed September 6, 2022.] Government of Canada 2022. Certificates of Age and Origin for Distilled Spirits Produced or Packaged in Canada Order. https:// laws-lois.justice.gc.ca/eng/regulations/SI-2009-61/FullText.html [Accessed March 31, 2022.] Government of Canada. 1980. Canadian Alcoholometric Tables. https://www.canada.ca/en/revenue-agency/services/tax/ technical-information/excise-act-2001-technical-information/ canadian-alcoholometric-tables-1980.html [Accessed March 31, 2022.] Government of Canada. 2022. Food and Drug Regulations. Canadian Whisky, Canadian Rye Whisky or Rye Whisky. https://www.laws-lois.justice.gc.ca/eng/regulations/ C.R.C.,_c._870/section-B.02.020.html [Accessed March 31, 2022.] Hiram Walker Archives. 1886. Handwritten laboratory notes of blending department describing formulations. Windsor, Ontario. Hiram Walker Archives 1940. Brand Book Index Hiram Walker & Sons Inc. Distillers and Bottlers. Windsor, Ontario. Hiram Walker Archives 1944. Obsolete Formulas Book of Cliff Hatch. Windsor, Ontario. Hiram Walker Archives 1956. Formulas Book 1956 to 1967. Windsor, Ontario. His Majesty Customs and Excise. Spirit Tables. Sikes Hydrometer. Part I and Part II. London. His Majesty’s Stationary Office. 1938, 1–65. Livermore, D. The Canadian Whisky Flavour Wheel. 2017. https://www.lcbo.com/content/dam/lcbo/PDFs/Whisky-WheelDr-Don-Livermore.pdf [Accessed April 1, 2022.] Livermore, D. The Keeper of History. The Canadian Whisky Master Class Volume 1. Hiram Walker & Sons Ltd. 2021, 1 – 40. Livermore, D. Blending 101. The Canadian Whisky Master Class Volume 2. Hiram Walker & Sons Ltd. 2021, 75–112. MacKinnon, T.L. The Historical Geography of the Distilling Industry in Ontario: 1850 – 1900. Thesis for the Master of Arts Degree. Wilfred Laurier University. 2000, 25–79.

Blending Canadian Whisky – A Review

Livermore

Otto, S.A. Gooderham & Worts Heritage Plan. A Report on the Buildings at the Gooderham & Worts Distillery and an Assessment of Their Heritage Significance. Report No. 2. Gooderham & Worts Distillery 1988, 1–25.

Parliament of Canada. 1898. Summary of Reports of Commissions and Committees since 1800, Special Cases, Etc. Volume 9.

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VOLUME 2 NUMBER 1

Winter 2022

EDITORIAL

GENERAL GUIDE FOR CONTRIBUTORS/AUTHORS EDITION 2021

CALL FOR PAPERS The call for papers is thus now on open invite with the lead science editor appointed. Authors should contact Gary Spedding, Ph.D. gspedding@jdsed.com in all matters concerning manuscript submission and addressing suitable areas of coverage. Other documents and guides for authors will also be found on the journal website. Such materials include notes on Ethical Publishing in the 21st Century, Guidelines for Contributors/Authors — Manuscript Formatting, and Preparation, and a Manuscript Submission: Conflict of Interest Declaration and Author Agreement Form. Peer review guides are also available. Manuscripts must be submitted in the English language, and, unlike many other journals, the JDS team will accept carefully cited authentic references published in other languages. Most papers today will carry an English title and often an abstract in English even if the main text is written in a different language. The journal is open to worldwide authorship with the aim of leaving no relevant work missed or inaccessible to the distilling community. All relevant translations of titles must be made and the non-English language speaking author will be encouraged to make use of professional translation services to convey all meaningful facts, data and truly expressed interpretation of all the material conveyed in their carefully written manuscripts. Peer reviewers will then be able to concentrate on the interpretation and significance of the science and results, and not on rewriting the paper.

SUBMISSION, ACCEPTANCE AND REVIEW PROCESS As for many journals, authors will submit articles to the lead science editor (noted above) for an initial screening. Based on content and subject matter, in relation to the general scope of THE JOURNAL OF DISTILLING SCIENCE

the journal, manuscripts will be either be rejected after this initial screening or, if suitable, will then be sent on for peer review. The peer review process here is the single-blind model. Manuscripts will be reviewed by three independent, anonymous expert referees. Reviewer reports, with comments and recommendations will be returned to the lead science editor within three weeks of their receiving the manuscripts and reviewer forms. Final editor assessments will be made and announcements issued to authors based on their acceptance or rejection decisions regarding their manuscripts. Occasionally manuscripts will be accepted with no revisions required. Reviewers are to supply notes and recommendations for any revisions needed — minor or extensive, and authors will be directed to address those prior to final acceptance and preparation for publication of their works. The process will follow with publication layout and final proofing of documents. Final proof copies sent to authors to be returned within one week of receipt to ensure timely publication. Final publication will appear according to the timeline set for the next issue of the journal. Authors will be notified as to which issue their article has met the deadline for.

MANUSCRIPT SUBMISSION NOTES Authors are responsible for their own content as submitted and will be allowed to use their writings and data elsewhere at their discretion. However, the layout of their work in the journal remains the copyright property of the publisher. The publisher will issue the necessary transfer of copyright documents after manuscripts have been accepted, peer reviewed, revised as necessary, and when being set for layout. If any doubts arise about this copyright process, the editor and publisher will be happy to explain

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what is involved and the details of your rights to use some or all of the material elsewhere. To summarize: in general you will retain all rights and responsibilities to material as expressed in your initial manuscript, however, US copyright rules will dictate as to what is owned by the journal based on their responsibilities in publishing the work. No page charges will be incurred, nor fees instituted for the request to have items appear in print in color. Any extended rework needed will be discussed with authors, editor and publisher as necessary. Manuscripts will not be accepted by the lead science editor unless accompanied by the signed form: Manuscript Submission: Conflict of Interest Declaration & Author Agreement Form. That form covers the topic of conflicts of interest (COI), for the group and individual authors. The lead or corresponding author will ultimately assume and accept global responsibility for submission of the paper. However, it is expected that all authors listed as contributing to the work will have signed off on any disclosure statements under the authority and signature of the lead/corresponding author or team leader. Full terms and conditions are expressed in that agreement document. In addition to the above statements, declarations as to the nature of funding for the research, or the writing (in the case of review papers) will need to be made. Any copyright material submitted as part of a manuscript belonging to or owned by other parties must be accompanied by the appropriate end use agreement and release authorization documentation. Authors will be asked to sign a “No Conflict of Interest” statement. All authors will, furthermore, respect any and all final decisions concerning publication by the editorial staff, the reviewers, SDST and the publisher of the JDS. Any complaints made by any party at any time will, however, be carefully and fairly considered with all due recognition of respected and accepted 57

international scientific publishing guidelines taken into account. The JDS aiming only to publish the finest and most ethically prepared and reviewed scientific papers, reviews, notes and reports. All guides and materials of interest can be found at http://artisanspiritmag. com/journalds/.

A NOTE ON CONFLICTS OF INTEREST Affiliations with or involvement in any organization or entity with any financial interest (such as honoraria, educational grants, supplier/manufacturer funding/ supplies, participation in speaker’s bureaus, membership, employment, fellowships, consultancies, stock ownership, or other equity interest, and expert testimony or patent-licensing arrangements), or non financial interest (including personal or professional relationships, affiliations, knowledge, biased views or beliefs) in the subject matter or materials discussed/presented in the manuscript are considered under the terms of actual or potential conflicts of interest.

Were sponsors or others involved at any stage of the process — research and or writing et cetera? Acknowledge or reference any further contributions to this paper or review — such as data analysis, statistical analysis, data collection, data management or data storage services, professional language translation services (writing/editorial assistance) or any other assistance or support. [See details on the CRediT process, dealing with manuscript and research associated contributions, under the main instructions for contributors/authors document for more on this important new development in publishing.]

A SUMMARY OF KEY POINTS FOR AUTHORS PUBLISHING IN THE JDS ETHICAL STANDARDS

The JDS publisher and editor aim to publish the finest scientific papers possible within its pages. Manuscripts will be peer reviewed — three reviewers per paper. The highest ethical standards only will be tolerated. Authors and reviewers and 58

all JDS staff will put forth their best efforts and aim to eliminate all biases and to report any and all conflicts of interest. PUBLICATION STYLE GUIDANCE

Instructions to Author Guides and other documents are to be viewed and signed off on for successful publishing within the journal. The guides will assist in the author(s) setting the right style for publication. The lead science editor will make the initial decision as to suitability of manuscripts for the journal and send on those passing initial inspection to three reviewers. All manuscripts will be published in English. JDS recommends you to seek translation services when necessary to help ensure manuscripts pass initial selection criteria. SINGLE-BLIND PEER REVIEW METHOD

Three leading experts will be chosen from the editorial review board to single-blind review your manuscripts. Authors’ names will be known to the reviewers — authors will not know the identities of their reviewer “committee”. The three reviewers will also not know who their “team members” are. The single-blind peer review method is in use for many scientific and medical journals. Like the alternatives there are advantages and disadvantages to this model. Reviewers will be chosen by the editor. Reviewers must attest to eligibility and without bias as to authors or topic before they will receive the actual manuscript and supporting documents. Additional commentary can be found in the Guides to Reviewers. AUTHORSHIP OF THE PAPER

All listed authors must have contributed to the work. To the conception, design or the acquisition, analysis or interpretation of the data, drafting the paper, adding to its value via revision and or giving final approval. All authors will agree to be accountable for all aspects of the work. And in ensuring that any questions raised, related to the accuracy or integrity of any part of the work, are appropriately investigated and resolved.

REFERENCING THE WORKS OF OTHERS

Credit must be given to all sources of information used in the study and as expressed in the text. Details of methodology and results should not be withheld or data points removed without reason. Failing to present data in contradiction of your prior published data is unacceptable. Manuscripts are often screened today for similarity or for detecting acts of plagiarism. Unauthorized reproduction of the work/writings of others is theft and may be identified as copyright infringement. CONFLICTS OF INTEREST

All authors must disclose any conflicts of interest (COI) related to their intended publication. The manuscript must not be submitted or published elsewhere at the time it is undergoing JDS review nor upon its acceptance without JDS agreement. A COI can arise if authors are paid by any commercial entity to write an article, to do the research for that article or compile a review. Ghosting/ghostwriting, whereby a third party writes an article submitted by others must be stated upon forwarding the manuscript for consideration. Other details provided above under “A note concerning conflicts of interest.” Materials submitted remain the property and responsibility of the authors but the presentation/ layout will be copyright assigned to the Publisher. Further details on these points will be found in the Manuscript Submission: Conflict of Interest Declaration & Author Agreement Form. Manuscripts will not be accepted by the lead science editor unless accompanied by the signed form. Legible manuscripts only accepted if they are set in the style described in the JDS Guidelines for Contributors/Authors — Manuscript Formatting and Preparation — Edition 2021 (or later year revision).

Manuscripts for consideration should be sent electronically to the Lead Science Editor.

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Gary Spedding, Ph.D. gspedding@jdsed.com

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