Wine & Viticulture Journal Autumn 2023 FREE VIEW

AUTUMN

• Ideas on reducing SO2 use

• The impact of crossflow vs membrane filtration on red wine quality

• The status quo of the carbon economy and vineyards

• Maintaining sales in trying economic times

• Tasting: Fiano

INDUSTRY ASSOCIATION COLUMNS

8 AGW (Lee McLean): We need to change the narrative around container deposit schemes

10 WINE AUSTRALIA (Martin Cole): Clarifying the overhaul of Australia’s wine industry research

10 ASVO (Andy Clarke): Practical solutions for achieving industry’s emission reduction roadmap goals to be discussed at CO23

WINEMAKING

15 CATHY HOWARD: Thinking of reducing your use of SO2? Some ideas on how to start the journey this vintage

17 Crossflow and membrane plate filtration: Their impact on the quality of different red wines under winery-scale conditions

23 Calcium tartrate instability: A new and increasingly widespread challenge that can be managed by safe and easy-to-apply means

30 Trends in the composition of Australian wine 1990-2021: Part 2 - alcohol and glucose plus fructose

34 AWRI REPORT: Understanding the greenhouse gas emissions of Australian wine production

VITICULTURE

38 TOWARDS NET ZERO (TONY HOARE): The carbon economy and vineyards: What’s the status quo?

41 Wine cultivars adapted to climatge change

47 Biochar impacts on soil carbon pools and nitrogen transformations in Queensland vineyard soil

52 Cover crops, soil organic carbon and a confluence of cobenefits: A glimpse from under the vines

55 From vine to wine: The impact of nitrogen fertiliser applications in a cool climate vineyard to address YAN deficiencies

59 ALTERNATIVE VARIETIES: Grillo

BUSINESS & MARKETING

61 Maintaining sales in trying economic times

63 World wine supply stable in 2022 as consumption faces downward pressures

65 Two decades of grape variety trends in Australia’s wine regions

TASTING

74 Fiano

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Andy Clarke

Peter Clingeleffer

Justin Cohen

Martin Cole

Andy Coppard

Ana Correia

Hilary Davis

Peter Dry

Peter Godden

Sandy Hathaway

Kieran Hirlam

Tony Hoare

Cathy Howard

António Jordão

Kate Kingston

Mark Krstic

Mardi Longbottom

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Sonya Logan, Editor

Alex MacKenzie

Joseph Marks

Lee McLean

Miguel Oliveira

Chris Pratt

German Puga

Giorgia Quinterno

Barbara Scotti

Gianni Triulzi

Harriet Walker

Eric Wilkes

Corrina Wright

Zhihong Xu

Jim Zerella

Kate Kingston Zhihong Xu

Chris Pratt

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If you’re up to your neck in vintage and have managed to take the wrapper off this issue of the Wine & Viticulture Journal and got as far as this page even though your copy only arrived in the mail in the last few days, thanks for taking the time! This time of year, we know our Autumn issue can lay unopened for a while until the demands of the current vintage subside long enough to allow some breathing space to even contemplate delving beneath its cover. And with this harvest looking like it is running a couple of weeks late in many parts of the country, that breathing space may take a little bit longer to materialise.

When you do have the time to work your way through this issue, here are just some of the highlights:

In his first column for the Journal, Australian Grape and Wine’s new CEO Lee McLean outlines why his organisation is campaigning against wine bottles being included in container deposit schemes. And it’s not just about the hit to the industry’s coffers (page 8).

We also have another new columnist in new ASVO president Andy Clark (page 11).

Speaking of columnists, long-time readers will remember when winemaker Cathy Howard and viticulturist Tony Hoare used to regularly appear in these pages offering thoughtful and informative discussions on all manner of winemaking and viticultural subjects, respectively. Both make a one-off appearance in this issue of the Journal (well, technically two appearances in Tony’s case as he has a Part 2 coming in our Winter issue). Cathy walks readers through some alternatives for reducing and maybe even replacing the use of sulfur dioxide (page 12). Meanwhile, for this issue’s Towards Net Zero feature, Tony lays

Cover

the groundwork for his second article - which will explore how to reduce carbon emissions in vineyards - by discussing what is currently known about the industry’s carbon footprint.

Tony’s article pairs well with this issue’s AWRI Report (page 34) which reveals the findings from the research body’s latest life cycle assessment of the industry’s greenhouse gas emissions.

In a second contribution to this issue from the AWRI, researchers present Part 2 of their analyses into the composition of Australian wine, this time focussing on alcohol, glucose and fructose (page 30).

In Viticulture, the CSIRO’s Peter Clingeleffer and Hilary Davis share the results of their assessment of 465 cultivars in CSIRO’s germplasm collection as they sought to identify varieties with characteristics best suited to climate change (page 41).

Speaking of winegrape varieties, Kym Anderson and his colleague German Puga from The University of Adelaide have followed up their article in the Winter issue of last year’s Journal where they explored trends in the varieties being grown in South Australia’s winegrape growing regions. In their latest article (page 65) they’ve extended their work to include the rest of Australia, pulling figures from various sources to deliver a comprehensive set of data.

And for the growing number of Fiano producers in Australia, be sure to read the results of our recent blind tasting, starting on page 77.

I trust the above and the remainder of this issue’s contents have been worth the wait. Here’s to a smooth end to the vintage!

Clarifying the overhaul of Australia’s wine industry research

By Martin Cole, chief executive officer, Wine Australia

Wine Australia’s approach to research investment has changed over the past year, and I’m pleased to have this opportunity to explain the key developments and rationale.

Nothing stays the same, and the challenges facing the wine and grape sector are many and evolving. Wine Australia has always strived to make the most of its grape and wine R&D levy income, deliver the maximum value for our customers, and address the sector’s most pressing issues through targeted investments. However, it became clear early in my tenure that we needed to consult, listen to and engage with our customers in new ways and further adjust our guiding principles and operational activity across the Research & Innovation (formerly RD&A) portfolio according to what we learned.

The end result of many meetings, workshops, surveys and discussions with passionate, experienced and well-informed sector representatives, as well as our valued research partners, has been an overhaul of the way we develop, fund and deliver research. We are now on a journey that will see more diverse sources of co-investment and funding opened up, including partnering in new initiatives across agricultural sectors, to supplement levy income and enable greater scale, collaboration and return on investment.

The other key change is that Wine Australia is now undertaking more end-to-end co-design of research projects with grapegrowers, winemakers and our other sector customers, research providers and relevant sector bodies to achieve maximum impact and application. This approach will shape the research done in partnership with and on behalf of the sector for years to come, and ensure its outcomes are the ones our customers need.

This hand-in-glove approach is also paying off in the adoption space: an increase in online resources coupled with equipping, training and partnering with local growers to develop agtech demonstration sites for regular grower-focused sessions, has seen an uptick in adoption and practice change. The commercialisation, communication and development of research outcomes is also a priority, converting knowledge gained through R&D investment into useable tools and practice change at the earliest opportunity.

A great example of one of these new co-designed projects is the Warm Inland Productivity and Profitability (WIPP) project, which has been developed and funded in collaboration with the NSW Wine Industry Association, Riverina Wine Grape Growers Association, NSW Department of Primary Industries (NSW DPI), Charles Sturt University and Food Innovation Australia Limited (FIAL).

Six months into the three-year term of the project, early outcomes include a winegrape trading platform to connect potential buyers and sellers of excess fruit, a new budgeting tool to assist growers in timely decision making and a local coordinator for the Riverina to aid in the adoption of best practice models and techniques and liaise between research providers and growers. The aim is to identify gaps in knowledge, skills, business management and vineyard practices relating to profitability, assist in building resilience and then transfer learnings to assist other warm inland wine regions, which are collectively dealing with more than their fair share of challenges.

Other current projects at various stages of consultation and development fall under the themes of no and low-alcohol (NOLO) wines and wine production and quality. Further, the ESG Business Plan and a related suite of projects in the sustainability space will be critically important in ensuring Australian wine’s market access, social acceptability and international reputation in the medium to long term.

While the work has only just begun to deliver on these projects and demonstrate the difference it makes to have the customer at the heart of their design and development, I’m heartened by the support and positive feedback we have received from both those directly involved and the many who stand to benefit in due course. WVJ

Practical solutions for achieving industry’s emission reduction roadmap goals to be discussed at CO23

By Andy Clarke, President, Australian Society of Viticulture & Oenology

CO23 conference to unpack sector’s Emissions Reduction Roadmap and offer practical solutions for achieving goals

The transition to net zero represents both a massive opportunity and challenge for Australia’s wine industry, from growing to selling our products. Businesses that show initiative, accept the challenge and adopt practical solutions for emissions reduction will be at a huge advantage.

The CO23 Conference, to be held on 15-16 June in Adelaide, is a not-to-be-missed event for all growers, winemakers, leaders and executives across the supply chain who want to be at the forefront of the transition to net zero, while remaining cost competitive.

The two-day, industry-driven conference will identify and unlock practical solutions that will assist wine industry stakeholders to achieve the industry’s emission reduction roadmap goals.

This will be an important forum for discussion on climate and regional realities, as well as the transformations required by both large and small businesses.

The conference program will include innovative lead presentations, case studies, breakout groups, short demonstrations and full-length presentations.

To register and for updates on the program visit www.asvo.com.au/events/co23-climatemitigation-conference

ASVO VITICULTURE SEMINARS

The ASVO viticulture seminar will be held over two afternoon sessions on 21 July and 4

August. Both seminars are planned for Friday afternoons to enable growers to connect over lunch, learn from interactive sessions and finish the week with a drink and networking.

The first seminar, ‘Maintaining established vineyards’, will focus on maintaining the long-term vine health, productivity and economic viability of vineyards. Presentations include comparing vine age performance, vine age and economic viability, old irrigation infrastructure and replacements.

The second seminar, ‘Establishing new vineyards’, will bring together information about establishing data-friendly vineyards, irrigation design for better water management, automation, optimising early vine growth, nutrition and weed control.

For further information about the seminars and to register visit www.asvo.com.au/2023asvo-viticulture-seminars

NOMINATIONS OPEN FOR THE 2023 ASVO SCHOLARSHIPS

ASVO is proud to continue to offer scholarships each year. The scholarship program aims to foster and promote continuing training and professional development for ASVO members. There are two funded scholarships available: one to attend the Advanced Wine Assessment Course (AWAC) and the other to attend the Advanced Viticulture Course (AVC), both run by the Australian Wine Research Institute.

Applications for the 2023 scholarships are open and will close on 31 March 2023.

Further information is available at www. asvo.com.au/asvo-scholarships

NOMINATIONS OPEN FOR ASVO FELLOWS

Each year the ASVO board elects Fellows of the society from members who have made a particularly outstanding and meritorious contribution to the grape and wine industry. The criteria for this honour include making a major contribution in an industry, scientific, educational or society role combined with membership of the society for at least 10 years. The ASVO Fellows who have been recognised to date represent the practitioners, researchers, teachers, entrepreneurs, consultants, mentors and leaders of our Australian wine community.

The ASVO board looks to its members to identify and nominate their peers that have made an exceptional contribution to the industry and the society over the course of their careers. If you know an ASVO member who fits the criteria of the award, please nominate them for consideration as an ASVO Fellow. Nominations to be considered in 2023 close on 30 July 2023. Please refer to the eligibility criteria when preparing your nomination. Nominations can be submitted throughout the year, online through the ASVO website www.asvo.com.au/nomination-fellowsociety/

Thinking of reducing your use of SO2? Some ideas on how to start the journey this vintage

By Cathy Howard, Winemaker/Partner, Whicher Ridge Wines, Geographe, Western Australia

In this one-off article for the Wine & Viticulture Journal, former regular WVJ contributor and winemaker Cathy Howard explores how alternatives to sulfur dioxide may help the industry reduce and maybe even replace its reliance on the additive to protect wine from microbial and oxidative spoilage.

SO2 – A REMINDER AS TO WHY WE USE IT

Sulfur dioxide (SO2) is a winemaking additive that plays a vitally important role in maintaining wine quality at different stages of wine production, from the grapes being harvested in the vineyard right through to wine being filled into bottles at the bottling line. SO2 has a mix of antimicrobial, antioxidant and anti-oxidising activities.

However, SO2 does have its negatives, which is now driving the research and trials into alternative products that could reduce its use or, ultimately, replace it in winemaking.

Excessive use of SO2 can have negative organoleptic effects. High free SO2 levels negatively impact the aroma and taste of a wine, producing an unpleasant burning sensation after swallowing. In addition, several sulfur volatile compounds are related to undesirable reductive odours in wine.

Esparza et al. (2020) states that three of these compounds were observed at concentrations above their threshold in faulted wines: hydrogen sulfide (H2S), methanethiol (MeSH) and dimethyl sulfide (DMS).

Further driving the push to find alternatives to SO2 additions in wine, and to reduce its use in wine, is a general wish to reduce preservative intake by wine consumers. According to Esparza et al. (2020), it is estimated that around 1% of the population has some clinical sensitivity to this food preservative, with increasing risk in asthmatic people.

To better understand how other products may work in reducing our reliance on SO2 to provide antimicrobial and antioxidative protection to our wines, we need to first revisit how SO2 interacts with other compounds in a wine to prevent microbial spoilage and oxidation.

WINEMAKING 101 – UNDERSTANDING HOW SO2 WORKS IN MUST AND WINE

When SO2 is added to must or wine, it is present in two main forms: bound SO2 and free SO2. It is the free SO2 that takes a leading role in the all-important antioxidant and antimicrobial reactions.

The free SO2 exists in two forms: molecular SO2 and bisulfite ion, HSO3-. It is the molecular SO2 which has the biggest impact on inhibiting the growth of bacteria and wild yeasts. The AWRI Winemaking Calculator is a downloadable app which has a handy molecular SO2 addition calculator that determines the appropriate level of free SO2 to stop microbial growth, with 0.825mg/L molecular SO2 being the level needed to eliminate cell viability. The calculator uses the two wine parameters pH and free SO2 to calculate a molecular SO2 value.

The pH of must and wine has an effect on the proportion of molecular SO2 present. The percentage of free SO2 in molecular form depends on the pH, with it being higher when the pH is lower. In wine with a higher pH, free SO2 is mainly present as the bisulfite ion (HSO3). Even though this form shows good activity against both micro-organisms and oxidation, the most active form of SO2 is the molecular type (SO2). Alcohol level and temperature also affect the equilibrium between bisulfite ions and molecular SO2, with molecular SO2 fractionally higher at higher alcoholic concentrations and temperatures.

Different compounds (sugars, carbon compounds) react with SO2, binding it, and acetaldehyde (MeCHO) is the most reactive. The product formed from the interaction between MeCHO and the bisulfite ion is stable and its formation reduces the activity of SO2 This reaction is an important one to keep in

mind as the ratio of the free and bound forms of SO2 can provide important information about the state of both white and red wines. SO2 binds very strongly to acetaldehyde and microorganisms present in wine. An indicator that oxidation or microbial spoilage has occurred in a certain wine is when that wine contains a very high proportion of bound SO2 compared to free SO2. The AWRI states that a comparatively high ratio of bound to free SO2 is when the free SO2 concentration is 25% or less of the concentration of total SO2 Microbial metabolism is one of the many factors affecting wine quality. In musts and wines, bacteria are very sensitive to SO2 and for this reason adding SO2 is a good technique for avoiding malolactic fermentation (when not desired) as well as for reducing the risk of fermentation spoilage by bacteria such as acetic or lactic acid bacteria.

Chemical oxidation in wine is another factor affecting wine quality. The antioxidant action of SO2 in musts works differently to the antioxidant action in wine.

In musts, the source of oxidation are polyphenoloxidase (PPO) enzymes reacting with phenolic compounds, mainly hydroxycinnamic acids and catechins, and converting them into quinones which are strong oxidants responsible for juice browning. The addition of SO2 stops the oxygen consumption in must itself by inhibiting PPO enzymes. One of these enzymes, tyrosinase, is normally present in grapes and it is totally inactivated by a relatively low addition of SO2 of approximately 50ppm. However, another PPO enzyme, laccase, produced by Botrytis cinerea, is less sensitive to SO2

In wine, the oxidation reactions come from a different source. Goode (2019) provides a good explanation of how oxidation happens.