HARVEST GUIDE
E T S L A B O R AT O R I E S | 2 0 2 2
IN THIS ISSUE pages 01-02
page 20
page 25
Maturity Monitoring
Non-Saccharomyces Yeasts Diagnostics
Potential Alcohol
The ETS Grape Maturity Monitoring Panels provide sets of analyses requested to monitor fruit maturity.
The PCR-based diagnostics can be used to determine implant success with commercial strains of non-Saccharomyces yeasts
Get a closer look at using glucose+fructose analysis to estimate potential alcohol.
pages 03-17
page 21-22
page 26
ETS Juice Panel
Measuring Proteins in Juice
Sugar Analysis
ETS has developed Enzyme-Linked Immunosorbent Assays (ELISA) to monitor proteins associated with heat instability.
Sugar can mean a number of things. See what's behind your "Residual Sugar" numbers.
Get the complete picture for informed winemaking with the harvest Juice Panel.
pages 18-19 Scorpions
pages 23-24
Find out what microbes are coming in on your grapes using Scorpion diagnostics.
Volatile Acidity Recognize the microbes and conditions that lead to VA formation to develop an effective monitoring and prevention program.
pages 27-30 Phenolics Program ETS offers a full suite of advanced HPLC-based analytical tools to evaluate phenolic compounds in grapes and wines.
pages 31-32
pages 43-46
pages 51-56
Aromas
Harvest Toolkit
Our Locations
Detect and prevent common (and uncommon) sensory flaws.
This short guide will give you the highlights of our most-requested Harvest testing.
p. 52- St. Helena
p. 55- Newberg
p. 53- Healdsburg
p. 56- Walla Walla
pages 33-38
page 47-48
p. 54- Paso Robles
The Impact of Wildfires
Harvest Satellite Analysis
ETS offers an extended panel for volatile smoke markers and a glycosylated markers panel this harvest.
Use this quick reference to see which Juice Analyses are offered at your local lab.
pages 39-42
pages 49-50
Wildfire Impact FAQ
Sampling and Shipping
Your most-asked questions, answered.
Make sure you get the most out of your results using these sampling guidelines.
MONITORING MATURITY ETS GRAPE MATURITY MONITORING PANELS AND SUGAR-PER-BERRY PANELS
W H AT A RE T H E S E PA N E LS ?
WHY M ON I TORI N G S U GAR P ER B ERRY?
The ETS Grape Maturity Monitoring Panels provide sets of analyses requested to monitor fruit maturity.
Monitoring Sugar per Berry, starting shortly after veraison, allows growers to determine the duration and rate of sugar loading. During this phase, vines synthesize and actively transport sugar into berries. At the end of this phase, Brix usually keeps increasing due to berry dehydration, however, and simply monitoring Brix cannot determine when the sugar loading phase stops. Conversely, when this point is reached, the actual quantity of sugar accumulated in each berry remains unchanged (see Fig 1).
They include the traditional measurements of juice solids (Brix) and acidity (Titratable Acidity and pH), enhanced by the addition of a more accurate determination of fermentable sugars (glucose + fructose) and malic acid, as the degradation of this organic acid is a well-known marker of ripening. They also include berry size parameters (volume and weight), as well as a less familiar measurement: sugar per berry. Sugar per berry is a calculation based on the average berry volume as measured by Dyostem®, the tool of choice to determine sugar on a per-berry basis. The Dyostem® also provides an assessment of berry volume variability expressed as a Coefficient of Variation (%) and a histogram of the berry volume distribution is provided in our reports.
The duration of the sugar loading phase, the time at which this phase ends, as well as the Brix achieved at that time, are all important indicators of wine growing conditions. Excessive or insufficient vigor, water availability and resistance to heat stress all have an impact. Vines under often desired moderate hydric stress conditions typically reach between 21 and 23 Brix at the end of sugar loading. In most cases vines with excessive vigor see their sugar loading stop before these levels are reached, as vegetative growth may compete with sugar synthesis and accumulation. Such vines also often poorly resist heat waves and tend to “shut down” more easily, which can prompt a sudden end of sugar accumulation in berries. At the other end of the spectrum, vines under excessive water stress, subject to nutrient deficiencies or diseased, also have difficulty reaching typical Brix levels at the end of sugar loading (see Fig 2). Furthermore, the end of sugar loading triggers a variety of maturity events influencing the development of grape aroma compounds and phenolics. It is often used as an indication of when to start grape phenolics measurements (see Vineyard Decisions – Grape Phenolic Panel p. 27).
1
ACTIVE SUGAR LOADING PERIOD
VERAISON
NO MORE ACTIVE SUGAR LOADING
DAY «0 »
(PHYSIOLOGICAL RIPENESS)
IN THE LABORATORY: A LOOK AT OUR DYOSTEM INDU ST R IAL NU M E R IC C AM E R A
PC + TOUCH SCRE E N
L E D L IGHT S
ANALYSIS PL ATE
P OTEN TIA L DEG RE E AT S U GAR LOAD I N G STO P ( % VO L . )
SUGAR QUANTITY PER BERRY (MG)
FIG 1: THE SUGAR LOADING CONCEPT FIG 2: SUGAR LOADING & VINE WATER STATUS MERLOT 2012, PAUILLAC
14
13
M O D E R AT E WAT E R RESTRICTION
12
N O WAT E R RESTRICTION
11
NUTRITION DEFICIENCIES ( N , K)
WATE R S TRE SS
H I GH YI E L D 10
0
5 1 2 3 4 6 7 8 P R E DAW N L E AF WAT E R P OT E N T I AL DU RIN G RIPEN IN G ( B AR , AB S O LU T E VALU E )
Working Together: ETS is proud to be par tnered with Fruition Sciences and Vivelys (D yostem ®), to help you better characterize vineyards, closely monitor grape ripening, and make the most informed harvest decisions.
2
JUICE ETS
3
PA N E L Winemakers rely on juice chemistry analysis for a more complete picture of must composition at harvest that goes beyond traditional TA, pH, and °Brix. This is critical as juice chemistry is often different from vintage to vintage. Combining modern tools gives vital insights to make informed vineyard management decisions, choose harvest dates, predict/adjust wine composition and facilitate fermentations. 4
AP P LY IN G J UIC E C H E MIST RY TO WI NE M AKI N G A thorough analytical picture gives winemakers the ability to better predict their wine composition, and plan appropriate winemaking strategies in response to changing must compositions. Whether you analyze your free-run juice, monitor your mid-fermentation chemistry, or do both, it is important to understand the analytical results in context within the fermentation process stage. Analyzing juice pre-fermentation provides data that gives winemakers the opportunity to identify anything unusual about the current vintage, and to compare differences in composition from vintage to vintage. These insights affect winemaking decisions including acid adjustments and fermentation strategy.
U S I NG J U I C E A NA LYS I S TO P R E D I C T W I N E COM P OSI T I O N Clients sometimes ask why they see a difference in the concentration of acids, or potential alcohol vs. final alcohol, when comparing their juice samples to mid- to end-stage fermentation samples. It is not unusual to observe differences between the levels of acids, potassium and sugar/potential alcohol in different samples from the same vineyard. Variations can occur depending on the vineyard sampling strategy and how representative the samples are of the vineyard. How juice samples are prepared matters, e.g. how thoroughly each grape sample is crushed and mixed. In white winemaking, the differences in composition between free run juices and the different press fractions are well known. In red winemaking, free-run juices obtained after filling tanks may not reflect the actual content of the tank, since components such as acids and potassium can initially be sequestered at high levels in grape tissue next to the skin. As the grape tissue breaks down during cold soak, fermentation, and maceration, the resulting extraction of acids and potassium from the tissue into the juice can contribute to the observed differences. Likewise, the sugar in raisins or shriveled grapes may take a long time to release during red winemaking, causing an underestimate of fermentable sugar and therefore potential alcohol. Mid-point analysis on the fermenting wine (analyzing glucose+fructose and ethanol) may give a more accurate picture of fermentable sugar and potential alcohol. All of these factors can contribute to the differences observed between juice samples and the final wine composition.
5
C ALIFORN IA G LO B AL DATA (AV E RAGE OF A LL VA RIETA L JUIC E PA NELS) Ye ar
B rix
Glu/Fru
pH
TA
M ali c
Tar t ar i c P ot as s i um
A m m oni a
N O PA
YAN
2021
24.2
250.9
3.49
5.3
2.07
5.1
1595
57
107
154
20 2 0 *
23.8
248.7
3.35
4.9
1.92
5.1
1780
68
126
154
2019
24.0
249.5
3.62
5.0
2.14
4.5
1656
61
122
175
2018
24.2
252.5
3.53
5.7
2.88
5.3
1563
56
110
156
2017
24.5
254.0
3.62
5.3
2.19
5.1
1859
69
120
174
2016
24.6
258.2
3.59
5.4
2.38
4.5
1690
69
147
203
2015
24.8
262.9
3.56
5.5
2.31
5.0
1748
75
120
180
2014
24.7
262.5
3.60
5.1
2.14
4.9
1665
66
112
166
C ALIFORNIA R E D G LO B AL DATA (A VERAGE OF A LL RED VA RIETA L JUIC E PA N E L S ) Ye ar
B rix
Glu/Fru
pH
TA
M ali c
Tar t ar i c P ot as s i um
A m m oni a
N O PA
YAN
20 2 1
25.3
264.2
3.69
4.6
1.80
4.8
1770
48
98
136
20 2 0 *
24.7
259.6
3.50
4.3
1.62
4.8
1911
56
111
157
20 1 9
25.1
261.0
3.73
4.5
1.92
4.16
1778
53
113
156
20 1 8
25.4
265.5
3.64
4.9
2.34
4.20
1654
45
95
131
20 1 7
25.4
264.0
3.73
4.7
1.93
4.73
2011
62
108
153
20 1 6
25.6
269.2
3.69
4.9
2.22
4.15
1845
66
135
189
20 1 5
26.0
276.3
3.69
4.9
2.23
4.54
1943
65
108
160
20 1 4
25.9
275.4
3.74
4.4
1.97
4.39
1805
58
99
145
C ALIFORNIA WH IT E G LO B AL DATA (A VERAGE OF A LL WHITE VA RIETA L JUIC E PAN E L S ) Ye ar
B rix
Glu/Fru
pH
TA
M ali c
Tar t ar i c P ot as s i um
A m m oni a
NO PA
YAN
20 2 1
23.1
237.6
3.30
5.9
2.33
5.3
1420
67
116
171
20 2 0 *
23.0
237.9
3.19
5.5
2.23
5.4
1649
80
140
206
20 1 9
23.0
238.1
3.51
5.5
2.36
4.8
1535
69
131
188
20 1 8
23.1
239.5
3.42
6.4
3.42
6.4
1472
67
125
180
20 1 7
23.6
244.0
3.52
5.9
2.46
5.47
1707
76
132
194
20 1 6
23.6
247.3
3.48
5.9
2.53
4.87
1534
72
158
217
20 1 5
23.7
249.8
3.43
6.1
2.39
5.39
1553
84
131
200
20 1 4
23.6
249.5
3.46
5.8
2.31
5.39
1525
75
125
187
*2020 vintage juice panels do not necessarily reflect “normal” harvesting times 6
A NA LYZING WI N E DURING FERM ENTATI O N Because the must components are in a state of flux from cold soak to post malolactic fermentation, many winemakers prefer to make incremental adjustments rather than rely on one initial or massive adjustment. Winemakers who are targeting a certain TA and pH or ethanol level, for instance, often check their wine chemistry again at the fermentation midpoint. These mid-point numbers are used to make ongoing and final fermentation adjustments. It's important to note that in ripe fruit, glucose + fructose numbers often appear higher than the corresponding °Brix results. This is because °Brix is measured as a percentage by weight, meaning brix values are greatly influenced by the density of juice. Glucose + Fructose is measured as weight by volume and is independent of juice density. A must with 23.3 °Brix will not have 23.3% by volume fermentable sugar. 7
SUGAR CONTENT Sugar concentration increases rapidly in grapes as they mature. This increase is usually due to sugar movement from the leaves to the fruit. During the final stages of berry development, berry dehydration may also contribute significantly to the final sugar concentration. Rates of sugar accumulation do vary from vintage to vintage. °Brix is a measure of soluble solids in juice and must. The soluble solids in grape juice are primarily sugars. Organic acids, however, have a significant impact on brix, especially with unripe grapes. °Brix is used as an estimate of sugar concentration and often as a predictor of potential alcohol, but is not a true measure of fermentable sugar. Two juices with identical °Brix may have very different final alcohol concentrations °B RI X
29
due to varying amounts of fermentable sugars. Observations over the last five vintages indicate that the amount of glucose + fructose per degree brix varies slightly from vintage to vintage. This can have a significant impact on potential ethanol predictions based solely on Brix. That said, many people use Brix to monitor maturity or sugar accumulation
°Brix is not a true measure of fermentable sugar. Two juices with identical °Brix may have very different final alcohol concentrations due to varying amounts of fermentable sugars.
The sum of glucose + fructose measures the two main sugars present in juice that can be fermented by yeast. This analysis provides a sound basis for estimates of potential ethanol in the wine. This additional analysis is an important supplement to °Brix testing when final ethanol predictions are critical.
C HA RDONNAY BY VINTAGE
27
2021
23
2020 2019 2018
21
19
17 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
°B RI X
CA BERNET SAUVIGNON BY VINTAGE
33
31
29
27
Brix
Brix
25
2021 25
2020 2019
23
2018
21
19 8/12
8/22
9/1
9/11
9/21
10/1
10/11
10/21
10/31
11/10
11/20
Date 8
N I T R O G E N C O M P O U N D S
Sluggish and stuck fermentations, coupled with sulfide formation, have become increasingly common and are often associated with deficiencies of yeast assimilable nitrogen in the must. However, excessive concentrations of certain nitrogen compounds have been associated with microbial spoilage and other fermentation problems.
vintage to vintage due to changes in ammonia and/or NOPA. Monitoring during harvest enable trends to be observed in accumulation and/or depletion YAN was overall lower in 2021, but with a normal trending pattern as compared to 2018.
Yeast assimilable nitrogen includes both alpha amino nitrogen (NOPA) and ammonia. Analysis of only alpha amino nitrogen or only ammonia nitrogen does not provide an accurate indication of total nitrogen status for a given must. Ammonia and NOPA can change independently of each other resulting in different ratios of these two YAN components.
Knowledge of nitrogen status is critical for effective fermentation management. Nitrogen compounds are essential macronutrients for yeast, and are required for cell growth, multiplication, and yeast activity. As with other juice chemistry components, YAN values fluctuate
YAN
C HA RDONNAY BY VINTAGE
220
YAN (mg/L)
170
2021 2020
120
2019 2018
70
20 8/12
8/22
9/1
YAN
9/11
9/21
10/1
10/11
10/21
10/31
11/10
11/20
Date
CABERNET SAUVIGNON BY VINTAGE
430 380 330
YAN (mg/L)
280
2021
230
2020 2019
180
2018
130 80 30 7/18 9
8/7
8/27
9/16
Date
10/6
10/26
11/15
AM M ONIA
C HA RDONNAY BY VINTAGE
185 165 145
Ammonia (mg/L)
125 105
2021 2020
85
2019 2018
65 45 25 5 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
AM M ONI A
C A BERNET SAUVIGNON BY VINTAGE
105
Ammonia (mg/L)
85
2021
65
2020 2019 2018
45
25
5 8/12
8/22
9/1
9/11
9/21
10/1
10/11
10/21
10/31
11/10
11/20
Date
A M M O N I A
Ammonia is the form of nitrogen nutrition most easily assimilated by yeast. Wineries routinely supplement nitrogen deficient musts with diammonium phosphate at the start of or during fermentation to provide adequate nitrogen levels. Additional ammonia analysis and adjustments during fermentation may also be beneficial in minimizing the risk of stuck fermentations and sulfide formation. Ammonia
results are expressed as mg NH3 per liter. These values may be expressed as nitrogen equivalents by multiplying NH3 results by 0.82. Monitoring ammonia trends is important to understand changes in the levels of this rapidly available nitrogen compound. An ammonia depletion trend was not observed in 2021. 10
N O P A
Alpha amino nitrogen, otherwise referred to as “Nitrogen by OPA”, or NOPA, is determined using a method specific for alpha amino groups. It is a measurement of primary amino acids usable by yeast. NOPA does not include proline, which is not utilized by yeast, or ammonia. NOPA results are expressed as mg nitrogen per liter. NOPA generally trends upward and is usually the largest component of the YAN.
NOPA
C HA RDONNAY BY VINTAGE
295
245
NOPA (mg/L)
195
2021 2020 145
2019 2018
95
45 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
NOPA
CA BERNET SAUVIGNON BY VINTAGE
165
145
NOPA (mg/L)
125
2021
105
2020 2019
85
2018
65
45
25 8/12 11
8/22
9/1
9/11
9/21
10/1
Date
10/11
10/21
10/31
11/10
11/20
AC I D B ALAN C E The acid composition of must is a complex balance of free hydrogen ions, acids, acid salts, and cations. Concentrations of these various components and their interactions influence many winemaking parameters. The principal objective of acid management is to achieve and maintain a pH favorable to optimum wine balance and stability. Vintage variations in any of the components that impact acid balance can result in unexpected changes in the final pH and TA of a wine. Monitoring the parameters that contribute to pH and TA is an important preview to how the vintage will affect overall acid balance in the wine.
12
TA R TAR IC ACID Tartaric acid is one of the two major organic acids found in grapes. It accumulates in grape tissue early during development and declines during ripening due to berry growth and dilution. Tartaric acid is not usually metabolized in grapes. It is present in grapes, must, and wine as a free acid and weak acid-salt complex. Tartaric acid-salts may precipitate, primarily as potassium bitartrate and calcium tartrate.
life of a wine. An increase in the ratio of the free tartaric acid to the tartaric acid salts will cause a decrease in pH. This will affect the flavor, balance, and stability of the final product. Tartaric acid is commonly used to adjust the acid balance of juices and wines. Understanding tartrate interactions is important in designing appropriate acidification strategies. The 2021 vintage had elevated levels of tartaric at harvest.
Both the formation and solubility of salts are affected by a balance of components that are in flux throughout the early 10
TAR TAR I C
C HA RDONNAY BY VINTAGE
9
8
Tartaric (g/L)
7
2021 6
2020 2019
5
2018
4
3 2 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
TAR TAR IC
8
C A BERNET SAUVIGNON BY VINTAGE
7
Tartaric (g/L)
6
5
2021 2020 2019
4
2018 3
2 8/12 13
8/22
9/1
9/11
9/21
10/1
Date
10/11
10/21
10/31
11/10
11/20
pH is a measure of free hydrogen ions in solution (which corresponds to the chemical definition of acidity) and is used as a gauge of wine acidity. Wine color, potassium bitartrate stability (cold stability), calcium stability, and molecular SO2 level are directly
PH
PH
related to wine pH. pH is also critical in relationship to microbial stability, interactions of phenolic compounds, and color expression. Overall, the 2018 vintage had lower pH as compared to the 2017 vintage.
C HA RDONNAY BY VINTAGE
4.2
4
pH (g/L)
3.8
2021
3.6
2020 2019
3.4
2018
3.2
3
2.8 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
PH
4.4
CABERNET SAUVIGNON BY VINTAGE
4.2
4
pH
3.8
2021 3.6
2020 2019
3.4
2018
3.2
3 8/12
8/22
9/1
9/11
9/21
10/1
Date
10/11
10/21
10/31
11/10
11/20 14
MA LIC ACID
Malic acid accumulates early in berry development and declines during ripening due to dilution and respiration. Viticultural practices and grape cluster environments may directly affect respiration rates of malic acid. Malic acid levels affect pH and titratable acidity. Malic acid is converted to lactic acid during malolactic fermentation, causing the loss of an acid group. The effect of this acid reduction on pH depends upon the initial amount
MAL IC
of malic acid and buffer capacity of the wine. Malolactic fermentation in wines containing low levels of malic acid and high buffer capacity will have little impact on wine pH. Malolactic conversion in wines with high malic acid and low buffer capacity can result in a substantial pH increase. Malic acid tends to be higher in cooler vintages. That said, 2018 had the highest malic acid levels for all varietals except Syrah as compared to the previous four vintages.
C HA RDONNAY BY VINTAGE
6.5
5.5
Malic (g/L)
4.5
2021 2020
3.5
2019 2018
2.5
1.5
0.5 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
MAL IC
CA BERNET SAUVIGNON BY VINTAGE
3.6
3.1
Malic (g/L)
2.6
2.1
2021 2020
1.6
2019 2018
1.1
0.6
0.1 8/12
8/22
9/1
9/11
9/21
10/1
Date 15
10/11
10/21
10/31
11/10
11/20
TIT RATAB LE ACIDI TY
Titratable acidity (TA) measures total available hydrogen ions in solution. This measurement includes both the free hydrogen ions and the undissociated hydrogen ions from acids that can be neutralized by sodium hydroxide. TA is the most widely used measurement of acidity in wine. Although generally considered a simple parameter, titratable
TA
acidity is actually a reflection of complex interactions between the hydrogen ions, organic acids, organic acid-salts, and cations in solution. Often there is no direct correlation between TA and pH. Two musts with similar titratable acidity may have very different pH values.
C HA RDONNAY BY VINTAGE
11.5 10.5 9.5
TA (g/L)
8.5
2021
7.5
2020 2019
6.5
2018 5.5 4.5 3.5 2.5 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
TA
CABERNET SAUVIGNON BY VINTAGE
6.9 6.4 5.9
TA (g/L)
5.4 4.9
2021 2020
4.4
2019
3.9
2018
3.4 2.9 2.4 8/12
8/22
9/1
9/11
9/21
10/1
10/11
10/21
10/31
11/10
11/20
Date 16
P OTASSIUM
Potassium is the primary cation present in grape tissue. Potassium concentration in the berry is a function of root uptake and translocation. Both are strongly affected by viticultural factors including choice of rootstock, potassium fertilization, and canopy management. Potassium moves into cells in exchange for hydrogen ions from organic acids. Potassium concentration is highest
P OTASSIUM
2800
near the grape skin. Crushing, skin contact, and pressing all influence potassium levels. Potassium is a critical factor in pH, acid salt formation, tartrate precipitation, and buffer capacity. Decreases in juice potassium are associated with decreased juice pH. For example, 2018 vintage California Cabernet Sauvignon harvested in November, had approximately 22% lower potassium values as compared to 2017. The pH for the 2018 vintage averaged 3.78 versus 3.95 for the 2017 vintage.
C HA RDONNAY BY VINTAGE
2600 2400 2200
Potassium (mg/L)
2000
2021
1800
2020
1600
2019 2018
1400
Conclusions
1200 1000 800 7/18
8/7
8/27
9/16
10/6
10/26
11/15
Date
P OTASSIUM
CABERNET SAUVIGNON BY VINTAGE
2750
Potassium (mg/L)
2250
2021 2020
1750
2019 2018
1250
750 8/12
8/22
9/1
9/11
9/21
10/1
Date 17
10/11
10/21
10/31
11/10
11/20
Juice chemistry is the foundation for the resulting wine. Producing wines with specific targets for ethanol and acid balance, while avoiding fermentationrelated problems, requires a thorough understanding of the juice chemistry. Individual components of the juice can and do change from vintage to vintage. Winemakers aware of these changes will be able to adjust their winemaking process, where necessary, to achieve their targeted wine styles.
JUICE SCORPIONS
Indigenous m i c robes com i ng i nt o t h e wi ner y on fr u i t i s o n e o f t h e most i m por t ant ent r y rout es for s poi lage organi s m s t h a t ca n ca u se s t uc k and s luggi s h fer m ent at i ons an d V A p ro b l e m s.
18
I
Production of high levels of volatile acidity prior to fermentation can also cause problems later in the production process, including possible impacts on the fermentation performance and wine sensory attributes.
Using Scorpions to see the full picture of spoilage microbes in the juice from incoming fruit gives the winemaker better situational awareness for potential problems that can occur during the cold soak process, in stuck or sluggish fermentations, or later during wine aging.
Large numbers of Acetic Acid bacteria on incoming fruit can carry through the fermentation and cause problems with VA production when exposed to air during barrel aging.
Volatile acidity in juice
In addition to causing sensory impacts, large populations of wild yeast can deplete the YAN in the must, resulting in a YAN deficiency for the Saccharomyces cerevisiae driving the fermentation. Winemakers who detect high levels of Hanseniaspora or Pichia in a must usually recheck YAN before yeast inoculation, and supplement YAN if necessary.
dentifying and quantifying yeast and bacteria that can cause spoilage during the winemaking process is the first step in preventing these spoilage problems.
Volatile acidity, measured as acetic acid, can be formed throughout the winemaking process. Both acetic acid bacteria and strains of wild yeast – particularly Hanseniaspora and Pichia – are commonly linked to volatile acidity production prior to and in the early stages of fermentation. Elevated VA levels often occur during the cold soak process, or between cold soak and fermentation during red wine production. The VA-producing spoilage microorganisms grow quickly during this time, producing increasing levels of acetic acid until fermentation conditions inhibit their growth.
W H AT W E ' R E LOOKING FOR...
Effects on fermentation
Likewise, if the Scorpions assay detects heterofermentative lactic acid bacteria, such as Lactobacillus brevis, L. kunkeei, L. hilgardii, L. fermentum, and Oenococcus oeni, in a juice, winemakers usually increase their monitoring of malic acid and microbe levels if the fermentation becomes sluggish or stuck. Early identification of the presence of these bacteria and recognizing the risk they pose to difficult fermentations is key to preventing VA formation in stuck fermentations.
HANSENIASPORA
Hanseniaspora (Kloeckera) is a wild apiculate yeast that is often present at high levels on incoming fruit. Hanseniaspora can initiate fermentation in the must and produce high levels of volatile acids, including acetic acid ACETIC ACID and ethyl acetate. It has been associated PICHIA BACTERIA with acid rot in grapes infected by Acetic acid bacteria are Botrytis cinerea. Population levels Pichia is a wild yeast that is often commonly associated with grapes usually decline as alcohol present at high levels on incoming and the winery environment. The concentration increases. fruit. Pichia can initiate fermentation, three groups of commonly detected resulting in production of high levels of acetic acid bacteria are Gluconobacter, volatile acids, including acetic acid and ethyl Gluconacetobacter and Acetobacter. Both acetate. These yeast have been associated Gluconacetobacter and Acetobacter can with fflms formed in barrels and tanks generate acetic acid from ethanol in the during storage. presence of oxygen. The presence of these organisms can cause elevated volatile acidity in wines exposed to air.
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Z Y G O S A C C H A R O M YC E S M A N Y W I N E R I E S A R O U N D T H E W O R L D U S E G R A P E C O N C E N T R AT E I N T H E P R O D U C T I O N O F T H E I R W I N E S . A LT H O U G H G R A P E C O N C E N T R AT E I S N O T T H E O N LY S O U R C E O F Z Y G O S A C C H A R O M Y C E S Y E A S T , I T I S C E R TA I N LY A C O M M O N S O U R C E F O R Z Y G O S A C C H A R O M Y C E S T O B E I N T R O D U C E D I N T O T H E W I N E R Y .
The primary species of Zygosaccharomyces typically associated with grape concentrate are Zygosaccharomyces bailii and Zygosaccharomyces bisporus. Recently, a different species, Zygosaccharomyces rouxii, was isolated from a fermenting concentrate sample provided by a client. In response to this finding, we modified the design of the Zygosaccharomyces Scorpions primer/probe combination to detect more species. The new Zygosaccharomyces Scorpions diagnostic detects an additional 7 species of Zygosaccharomyces for a total of 9 species.
W H AT W E ' R E L O O K I N G F O R . . . Zygosaccharomyces bailii Zygosaccharomyces bisporus Zygosaccharomyces rouxii Zygosaccharomyces lentus Zygosaccharomyces mellis
Zygosaccharomyces parabailii Zygosaccharomyces pseudobailii Zygosaccharomyces pseudorouxii
Zygosaccharomyces kombuchaensis
N O N - S A C C H A R O M YC E S
Y E A STS D I AG N O ST I CS
Several providers of commercial yeast to the wine industry are offering strains of non-Saccharomyces yeast for use in the winemaking process. These yeasts can be used as bioprotective agents to reduce the impact of indigenous nonSaccharomyces strains as well as a way to reduce SO2 use prior to fermentation. In addition, these yeast strains may provide improvements via increased aroma complexity, wine structure and mouthfeel. In response to the increased use of these yeast strains by our clients, ETS has developed a series of PCR-based diagnostics to detect the presence of the individual strains; Metschnikowia pulcherrima, Lachancea (Kluyveromyces) thermotolerans, Torulapsora delbrueckii, and Pichia kluyveri. The PCR-based diagnostics can be used to determine implant success with the individual strains. They can also be used with the ETS Juice Yeast Scorpion Panel to look at the efficacy of these strains at reducing levels of Hanseniaspora uvarum and Pichia membranifaciens, commonly observed in must samples. The diagnostics can be requested for individual yeast species, or as a complete panel.
W H AT W E ' R E LOOKING FOR... NONS AC C H A R O M YC E S YEAST PANEL •
Metschnikowia pulcherrima
•
Lachancea (Kluyveromyces) thermotolerans
•
Torulapsora delbrueckii
•
Pichia kluyveri
INDIVIDUAL YEAST A N A LY S E S •
Metschnikowia pulcherrima
•
Lachancea (Kluyveromyces) thermotolerans
•
Torulapsora delbrueckii
•
Pichia kluyveri
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MEASURING PROTEINS IN JUICE AND F E R M E N TAT I O N SAMPLES 21
ETS has received an increasing number of requests to develop a method for determining the efficacy of bentonite fining in juice or during fermentation. Traditional Heat Stability tests can be difficult to perform on juice and fermenting samples. ETS has developed methods to directly quantify two proteins produced by Vitis vinifera in response to biotic and abiotic stress. These proteins, chitinase and thaumatin-like protein (TLP), are very resilient and persist through the fermentation
process. Both proteins have been implicated in haze formation although chitinase may play a larger role in heat stability issues. ETS has developed Enzyme-Linked Immunosorbent Assays (ELISA) to detect the individual proteins. Extensive testing last year indicates a linear response between addition of bentonite and removal of both chitinase and TLP. The ELISA based analyses are applicable to monitoring bentonite fining of juice, as well as bentonite fining during fermentation.
C hit inas e and N TU R e sp o n se t o B e n t o n i t e A d d i t i o n i n J u i c e 70.0 60.0 50.0 40.0 30.0
Chit inas e (ug/L )
NTU
20.0 10.0 0.0
0
1
4
2 3 B e n t o n i t e ( LB S / K G A L)
5
R es pons e of Chit i n a se a n d T LP t o B e n t o n i t e A d d i t i o n i n J u i c e 14.0 1 2.0 10.0
8.0 6.0
Chit inas e
TLP
NTU
4.0 2.0
0.0
0
1
2
5
3 4 B e n t o n i t e ( LB S / K G A L)
Juice Protein Panel • •
Chitinase Thaumatin-Like Protein 22
V O L AT I L E is strictly speaking a measure of the volatile acids in wine, although in the real world the contribution of volatile acids other than acetic acid is negligible. VA is a normal component of wines at moderate levels (normal concentrations range from 0.3-0.9 g/L of acetic acid), but very quickly becomes undesirable as levels rise. The sensory threshold is around 0.9-1.0 g/L, depending on the style of wine, and the U.S. government sets legal limits of 1.2 g/L in white wine and 1.4 g/L in red wine.
E T H Y L AC E TAT E Although not an acid, ethyl acetate is considered by some to be a component of VA. As an ester formed by ethanol and acetic acid, it is often linked to increased production of VA. From a sensory point of view, ethyl acetate is often classified as a “VA taint”, and its "nail polish remover” odor is often a telltale sign of high VA. Similar to acetic acid, there is a fine line between complexity and spoilage: small amounts of ethyl acetate can contribute “fruitiness/sweetness” or other positive characteristics to a wine at low levels. Normal concentrations are usually less than 100 mg/L, while the sensory threshold is generally 130-150 mg/L, depending on the wine style. 23
CO LD S OA K / E ARLY S TAG E F E R M E NTATI O N
VO L AT IL E AC I DI T Y ( V A )
Acetic Acid can be produced prior to fermentation by Acetic Acid Bacteria and wild yeast in compromised fruit. It’s unusual to see alcohol present in juice before fermentation, but if clusters experience fungal rot or other types of damage (such as bird or insect damage), wild yeast in the vineyard can begin fermenting the juice that is leaked out. Acetic Acid bacteria can then convert the alcohol to acetic acid, causing “sour rot” and leading to high VA levels before fermentation has even begun.
Ethyl Acetate is often produced in the early stages of fermentation, and can be a particular problem in native fermentations with a slow start. Native yeast, especially Hanseniaspora, are the main Ethyl Acetate producers at this stage. Note that the Hanseniaspora can consume most or all of the YAN in the must very early in the fermentation, although they will only produce alcohol up to around 6%. High levels of Hanseniaspora and low YAN concentrations can contribute to stuck fermentations.
ACIDITY The two components commonly associated with "VA taints " , Acetic Acid and Ethyl Acetate, can be formed by both yeast and bacteria - and in the case of bacteria, can be formed with or without oxygen present.
PRI MA RY F ER M EN TATI O N
Acetic acid production in primary fermentation is generally caused by yeast, including Saccharomyces and other species, but can also be formed by bacteria. The native yeasts Hanseniaspora and Pichia can drive fermentations up until around 6-7% alcohol, at which point they become stressed by the alcohol. Saccharomyces is more competitive as it is tolerant to and produces higher alcohol levels. In certain situations, the native yeasts respond to the changing
fermentation conditions by elevated levels of acetic acid.
producing
Bacteria, usually Lactobacillus, can also generate acetic acid from sugar and can often produce high levels of VA in stuck and sluggish fermentations. Oenococcus oeni, the bacteria used for inoculating most malolactic fermentations can also produce acetic acid from fructose. This frequently occurs at the end of malolactic fermentation if there is still fermentable sugar remaining in the wine.
Ethyl Acetate production during fermentation is significantly impacted by the yeast strain and fermentation temperature. Although Saccharomyces cerevisiae will produce ethyl acetate, research has indicated that some of the Saccharomyces bayanus strains are more likely to form ethyl acetate in cold fermentations.
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POTENTIAL ALCOHOL
The amount of fermentable sugar (glucose and fructose) in juice and the average conversion rate of sugar into alcohol can be used to predict the potential alcohol level in wines.
Q:
WHAT’S THE BEST WAY TO PREDICT POTENTIAL ALCOHOL LEVELS?
Predicting potential alcohol levels in finished wines sounds simple, but there is more than one way to measure “sugar”, and formulas to convert this sugar into potential alcohol often miss the mark.
Q:
HOW ACCURATE ARE POTENTIAL ALCOHOL ESTIMATES?
Our clients have reported that glucose + fructose values improve the quality of their predictions, but it is important to remember that yeast populations and fermentation conditions vary, and any prediction of potential alcohol is only an approximation. Alcohol conversion ratios can be variable, so it is possible your actual alcohol may be lower or higher than the estimate. Many of our clients have found that the conversion rates observed for their own yeasts and fermentation conditions remain relatively constant, and they use their internally observed conversion rates to calculate potential alcohol content based on their glucose + fructose values. With white wines, predictions are usually fairly accurate. With red wine, however, getting a truly representative juice sample can be a challenge and can affect potential alcohol predictions. A juice sample taken soon after a tank is filled may not take into account un-popped berries, unripe berries (less sugar and more acids), and raisins (sometimes an overlooked source of large amounts of sugar, acid, and potassium). We suggest sampling after an initial 10°Brix drop, and analyzing the fermenting sample for glucose + fructose and alcohol simultaneously for a more accurate potential alcohol estimate. Proper sample preparation is key to accurate results. At ETS, juice samples are centrifuged before analysis, and then mixed by inversion to avoid stratification, ensuring the most accurate results. Particulates have a minimal impact on refractometry, but can have a large impact on densitometry results. 25
The “old school” method was to multiply °Brix by 0.6. One degree Brix is defined as 1 gram of sucrose in 100 grams of aqueous solution. However, grape juice does not naturally contain sucrose, but rather glucose, fructose, and a variety of organic acids and other dissolved solids. So when used for grape juice, °Brix is actually just an approximation of dissolved sugar, not an accurate representation of the fermentable sugars, and using ºBrix for estimating potential alcohol adds an additional layer of uncertainty to alcohol predictions. Differences between ºBrix and actual fermentable sugar content are even more pronounced in high ºBrix fruit and in fruit affected by fungal growth. How ºBrix is measured also has an influence. Differences exist between ºBrix by refractometry, densitometry (using either hydrometers or digital instruments), and other secondary measurements. The differences among the various measurement techniques are quite unpredictable depending on sample composition. A more modern calculation that has proven to be more accurate uses glucose+fructose analysis, which provides a more accurate measurement of the levels of fermentable sugar compared to using ºBrix. Note that in ripe fruit, glucose + fructose numbers often appear higher than the corresponding ºBrix results, because ºBrix is measured as a percentage by weight, meaning ºBrix values are greatly influenced by the density of the juice, while glucose + fructose is measured as weight by volume and is independent of juice density. An official conversion rate formula used in Europe is: Potential Alcohol (% vol) = glucose + fructose (g/L) / 16.83. In practice, rounding the 16.83 conversion factor to 17 is common.
SUGAR ANALYSIS GLUCOSE + F RU C TOS E
°B RIX °Brix is a measurement of the apparent concentration of sugar. It is commonly used for grape juice and must and is expressed as a percentage by weight (% w/w). One degree Brix is defined as 1 gram of sucrose in 100 grams of aqueous solution. When the solution contains dissolved solids other than pure sucrose, as is the case for grape juice and must, the °Brix is only an approximation of dissolved sugar.
In grape juice, Glucose + Fructose analysis measures the combined concentrations of the two main sugars present that can be consumed by yeast, also known as "fermentable sugars." Compared to °Brix, Glucose + Fructose can provide a better estimate of potential alcohol concentration after fermentation. In wine, “residual sugar” usually refers to the sum of Glucose + Fructose, an indication the amount of fermentable sugars remaining post fermentation, which is also an indication of ‘dryness’. Sucrose is not captured by this test. If it has been used in the winemaking process (such as for chaptalization of must, secondary fermentation of sparkling wine or added as a sweetener) measurement of Glucose + Fructose alone is usually not adequate – instead see Glucose + Fructose (Inverted)
In the wine industry, a term like “sugar” can mean different things. Clients often request testing for “RS”, but this term can be very ambiguous.
R E DU C I NG SU GA R Historically, “Residual Sugar” was measured by the Reducing Sugar method. This test derives its name from the ability of most sugars in juice or wine to ‘reduce’ other compounds. The most common reducing sugars are glucose and fructose. However, the method does not distinguish between fermentable and nonfermentable sugars, or other ‘reducing’ compounds for that matter, and these other compounds may contribute to reported results. Because of these limitations, the Reducing Sugar method is no longer the preferred choice to monitor completion of primary fermentation.
G LUCOS E + F R UCTOS E ( I NVERTED )
G LU COS E A ND F R U C TOSE PANEL The Glucose and Fructose Panel provides the individual levels of glucose and fructose, in addition to their combined concentration. This test is often requested to investigate or remedy stuck or sluggish fermentations.
Inverted Glucose + Fructose provides the sum of the concentrations of glucose and fructose after “inversion” of the sample. Inversion is a process by which sucrose is broken apart into glucose and fructose, so that it can be measured and included in the reported results. Hence, this test is useful when “Residual Sugar” is required after chaptalization of must, secondary fermentation of sparklings or whenever sucrose has been used as a sweetener in wine, other alcohol beverages or spirits. 26
BUILDING A PHENOLICS PROGRAM ETS offers a full suite of advanced HPLC-based analytical tools to evaluate phenolic compounds in grapes, juice, fermenting must and wine. The range of phenolic analyses allows flexible use and implementation to suit individual needs.
VINEYARD DECISIONS GRAPE PHENOLIC PANEL Phenolic compounds in red wine grapes are directly linked to eventual wine flavor, color and aging characteristics. The grape phenolic panel can characterize site to site variation as well as within site differences. It works well as a prediction tool for describing vintage effects on potential phenolics and is a great tool for vineyard research projects. It is very sensitive to changes in phenolic compounds occurring during grape maturation. The changes in grape tannin are particularly important for red wine picking decisions. The grape phenolic panel can track changes in seed ripening, skin tannin extractability and tannin modification. Dilution and concentration effects on tannin and other phenolic components can be monitored with the Grape Phenolic Panel particularly when used in conjunction with Grape Water Content.
27
U N DERS TA N DI N G RAW MATERI A LS GRAPE PHENOLIC PANEL
Successful winemaking strategies require accurate information on grape composition. Winemakers use this panel during fermentation to reach target levels of tannin for specific wine styles, to monitor seed extraction, for adjusting tannin modification through oxygenation and for decisions on extended maceration and pressing.
M A N AG I N G FER M E N TAT I ON
RAPID PHENOLIC PANEL FOR WINE Phenolic compounds are extracted from grapes during fermentation and maceration. Monitoring the phenolic composition of the must during fermentation can greatly enhance a winemaker’s control of the process. Juice bleeds, fermentation temperatures, pump-over or punch down regimes, the use of rack-andreturn, oxygen or air additions and press timings can all be fine-tuned with feedback on changes in phenolic composition. With this information, winemakers can adapt winemaking practices to fit the vintage and successfully create wines of a target style.
S E T T IN G TARGETS
RAPID PHENOLIC PANEL Phenolic composition is one of the main components of red wine style. The amount of tannin and its composition is the foundation of a wine’s structure. There are no “correct” values for these parameters. A winery must define their own style as a brand and for individual products within that brand. Integrating phenolic information into stylistic choices requires an understanding of the impact of tannin on the sensory profile of wines. For a winery new to this information a good strategy is to analyze a selection of recent products. Recent production lots, finished wines and competitor’s products are good choices. Tasting products with analytical information allows winery staff to build the connections between taste and analytical information. Taste is the final arbiter of style but a clear understanding of the relationship of taste and analysis is needed to turn analytical information into action.
WI N E LOT CHA RAC TERI ZATI O N
B OTTLED W I N E C HA RAC TERI ZAT I ON
After the completion of fermentation/maceration, a wine lot typically represents a specific vineyard and fermentation tank. This is an excellent point for collecting quality control data. A comprehensive review of production lots is a powerful tool for monitoring block to block variation and the effects of winemaking practices. Analysis of finished production lots early in the vintage is very useful for changing fermentation practices and targets later in the vintage.
Many wineries establish QC benchmarks for phenolic content immediately after bottling. This is especially useful for determining product consistency and for monitoring wine development during aging.
RAPID PHENOLIC PANEL
B LEN DI N G
RAPID PHENOLIC PANEL FOR WINE OR RED WINE PHENOLIC PROFILE Winemakers interested in consistent tannin and color levels benefit by comparing the phenolic profiles of bulk wines prior to blending. Potential blends can be compared to target phenolic levels and benchmarks prior to final blend.
RED WINE PHENOLIC PROFILE
FI N I S HED W I N E EVA LUATI O N S
RED WINE PHENOLIC PROFILE A historical review of products from within a winery and evaluation of similar products from other producers is an excellent way to establish phenolic benchmarks. This is often the first step in building an integrated program of phenolic analyses. A careful review of finished wines combined with sensory evaluation and market feedback can identify program strengths and weaknesses. The identification of desirable levels for key phenolic components creates targets that can be incorporated into process control points in the vineyard and winery. 28
E TS R A P I D P HENOL I C PANEL S G R AP E P HENOL I C PANEL The rapid phenolic panel for grape berries includes a 'wine-like' extraction of grape berries along with analysis of total anthocyanins, polymeric anthocyanins, quercetin, tannins and catechin in the resulting extract. It is an excellent tool for monitoring phenolics development in grapes, evaluating vineyard and vintage variation, viticultural experiments, and can help guide tannin management decisions during winemaking. Submitting samples as berries is recommended.
CO MP ONENT S N A ME
UN I T
TEC HN I Q UE
Catechin Catechin/Tannin Ratio
mg/L
HP L C Ca lc u l at ion
Polymeric Antho cyanins
mg/L
HP L C
Polymeric Antho cyanins/Ta n n i n rat io
Ca lc u l at ion
Q uercetin glyco sides Tannins
mg/L mg/L
HP L C HP L C
Tot al Antho cyanins
mg/L
HP L C
R A P I D P HENOL I C PANEL - WIN E The rapid phenolic panel for wine provides a snapshot of important phenolic compounds with next day results. This information can help guide decisions on adjusting fermentation and maceration processes and blending decisions and works well as a complement to the rapid phenolic panel for grape berries to monitor vineyard effects on wine phenolic composition.
CO MP ONENT S N A ME
UN IT
TECHN IQ U E
Catechin Catechin/Tannin Ratio
mg/L
HP L C Ca lc u l at ion
Polymeric Antho cyanins
mg/L
HP L C
Polymeric Antho cyanins/Ta n n i n rat io
29
Ca lc u l at ion
Tannins
mg/L
HP L C
Tot al Antho cyanins
mg/L
HP L C
C A S E S T U DY:
HARSH TAN N IN S
B AC KG RO UND : Wines from a young Syrah vineyard were extremely tannic and harsh. AN A LYS I S : Client submitted grape samples for the ETS Grape Phenolic Panel RE S U LTS : C AT EC HI N TANNI N SYRAH GRAPES
15 mg / L
TOTAL AN TH O CYAN IN S 943 m g/L
Q U ERCE TIN GLYCOSIDE S 167 m g/L
PO LY MER I C AN TH OCYA NI NS 84 m g/ L
1740 mg / L TA N NIN A ND QUE RC E T IN GLYCOSIDES WERE BOTH VERY HIGH IN THE GR AP E S A M P LE . C AT EC HIN WA S QUITE LOW, PARTICULARLY F OR THE HIG H LEV E L O F TA NNIN WIT H A CATECHIN:TANNIN RATIO OF 0.008.
D I S C U SS I ON AND AC T I ON: Syrah grapes can have very high levels of tannin in the skins. Seeds, however, tend to ripen early so it is rare to see high catechin in Syrah grapes or seed tannin problems in wine. In this case, the problem seemed to be related to high skin tannin from excessive sun exposure. Skin tannin and quercetin glycosides increase with direct sun exposure. Sun exposed grapes synthesize quercetin glycosides in the skins to help block ultra violet light and simultaneously synthesize tannin to mitigate UV damage. The canopies were small and most grape clusters were in direct sunlight. The client installed a shade cloth trial the following vintage and was able to reduce tannin and quercetin glycosides in the shaded treatments. Looking at vineyard variation, they found higher tannin in grapes from weaker sections of the vineyard and found a strong relationship between trunk diameter and grape skin tannin. Vines with smaller trunks had more tannin in the grape skins. Using trunk diameter as a guide, the client increased vineyard inputs in weaker areas to improve growth. Shade cloth was installed in all the Syrah blocks. Tannin levels were reduced in both grape and wine samples and wines had improved textural qualities. As the vineyard matured, vine size and natural shading increased and tannin concentrations declined to non-problem levels. 30
EUCALYPTOL
MONITORING GLUTATHIONE
Since the discovery of eucalyptol (1,8-cineole) in red wines by ETS Laboratories in 2003, we’ve detected and measured eucalyptol in a large variety of wines exhibiting “eucalyptuslike” aromas. Flavors perceived during tasting were usually strongly related to concentrations of eucalyptol. Regardless of the grape variety, trace levels close to 1 ppb are associated with “fresh”, slightly “minty” notes. In the low ppb range, “minty” or “fresh bayleaf” aromas become stronger, and more easily identifiable as “eucalyptus” as concentrations increase. Wines with strong “eucalyptus” odors may contain more than 20ppb of eucalyptol.
Glutathione is not an aroma compound itself, but is a powerful antioxidant that protects white wines and rosés from oxidation and loss of aroma or flavor.
Eucalyptol’s sensory impact in wine is considered more or less desirable depending on the grape variety. Wines from southern Rhône and Mediterranean varieties seem better able to accommodate the characteristic well. Moderate levels can be appreciated in wines from Bordeaux varieties. Whereas with Pinot Noir, even trace levels can detract from varietal expression. Application: As eucalyptol may be mostly contributed by eucalyptus-derived MOG (leaves, bark debris…) hiding in grapes, analyzing grape samples before harvest is mostly pointless, and routine testing is not offered by ETS Laboratories. On the other hand, wine analysis assists winemaking teams in objectively documenting their sensory impressions and managing a strong flavor component. Unlike IBMP and smokederived compounds (see p. 38), eucalyptol is relatively slow to extract during red winemaking, making shorter macerations a valid strategy to minimize impact. Winemakers who wish to minimize or maintain consistent levels of “eucalyptus” character will also benefit by determining eucalyptol concentrations in distinct wine lots prior to blending. Eucalyptol- Eucalyptus traits are considered typical in some “cult” wines; on the other hand, in excess this character can be overwhelming. Even a slight “eucalyptus” note can interfere with delicate varietal aromas, and can have a detrimental influence on certain grape varieties.
31
A low level of glutathione in grapes leads to lower levels in the juice, and early losses of aroma compounds. Glutathione levels fluctuate during production, as the compound can be absorbed by yeast and then released after fermentation. If final glutathione levels are low in young wines, the wines will experience faster loss of fresh varietal and fruity aromas, and poor aging potential. Monitoring glutathione levels can be beneficial through out the winemaking process to maximize white wine aroma and flavor, and prevent premature aging. Glutathione, a natural grape antioxidant, can protect the aroma and flavor of white and rosé wines and prevents premature aging.
AROMAS 1
The glutathione content in grapes indicates their antioxidant potential, and can be influenced by a number of factors including soil nitrogen, vineyard practices, and grape maturity levels.
2
Analyzing changes in glutathione levels during production helps to pinpoint where in the process glutathione is being lost – often from contact with air or exposure to copper residues.
3
A testing program can also identify winemaking processes that boost glutathione release after fermentation, and increase levels in wines.
IBMP Isobutylmethoxypyrazine (IBMP) is the most important methoxypyrazine, a group of molecules responsible for very distinctive vegetal aromas in Sauvignon Blanc and a variety of red wines, mainly from the Cabernet family. In Sauvignon Blanc, these compounds add an often desired “grassy” character. In red wines however, the “green bell pepper” flavor is largely unpopular. Excessive IBMP levels lead to disappointing ratings and mixed success in the marketplace. The “green bell pepper” flavor in wine depends primarily on IBMP levels in harvested grapes. Once grapes have been picked, IBMP levels are not easily altered by standard winemaking processes. Application: The intensity of “green bell pepper/grassy” characters in wines can be predicted by measuring IBMP in grapes right before harvest. Grape screening of IBMP helps identify “problem” vineyards or blocks. Since IBMP decreases during grape maturation, monitoring IBMP levels throughout ripening is a unique tool for assessing “aromatic maturity”. It allows targeting harvest dates based on desired aroma characteristics. Monitoring IBMP from the early stages of the ripening process can greatly improve fruit quality from underperforming vineyards. Levels in grapes are well known to be linked to vine vigor, canopy and water availability, with severe heat occasionally causing IBMP’s natural degradation to stop. Once the kinetics of IBMP accumulation and degradation in specific sites are understood, viticultural practices can be modified accordingly. Once grapes have been picked, IBMP levels are not easily altered by standard winemaking processes. The IBMP potential of grapes can be grossly underestimated from juice samples, making whole berries the preferred sample in most cases. Analyzing juice samples may be relevant in white winemaking, however. IBMP (2-Isobutyl-3-methoxypyrazine) is the main compound responsible for the “green bell pepper” aroma in wine. 32
WILDFIRE IMPACT PANELS
VO L AT I L E M A R K ER S - Basic Panel ETS has been offering this Basic Panel of guaiacol and 4-methylguaiacol (guaiacols) which are the primary markers of smoke impact volatile (free) markers since 2008. Despite its simplicity, it has an excellent track record for assessing wildfire impact with pre-harvest grape samples, small-scale fermentation samples (micro-ferments), and production wines before contact with oak. Notably, it’s utility was confirmed by the 2018 Mendocino Complex Fire Lake County Winegrape Commission Study. Participants in this study were the University of California Cooperative Extension (UCCE), the Australian Wine Research Institute (AWRI), and the AWRI Commercial Services. (Please see “From Blaze to Bottle: Smoke Gets in Your Wine”by Glenn McGourty in the January 2020 Issue of Wine Business Monthly).
VO L AT I L E M A R K ER S - Extended Panel ETS offers also an extended panel of volatile (free) smoke markers. In addition to guaiacol and 4-methylguaiacol (guaiacols), this panel measures the secondary markers of smoke impact o-cresol, m-cresol, p-cresol, phenol, syringol and 4-methylsyringol. This extended panel is available for grapes, small-scale fermentation samples (microferments), and wines. Compared to the Basic Panel, additional markers allow more complete assessments of wildfire impact, and provide useful information with moderately oaked wines (e.g. from so-called “neutral” barrels, which often contribute low amounts of guaiacols making interpretation of results very difficult).
33
G LYCOSY L AT ED M A R K ER S PANEL In 2020 ETS finalized a unique panel of glycosylated (bound) smoke markers using a state-of-theart combination of solid phase extraction, liquid chromatography, and triple quadrupole mass spectrometry (SPE/HPLC/MS/MS - QQQ). ETS has worked behind the scenes with the Wine Institute Technical Committee, the AWRI, and several major wineries to reach an agreement on a common list of glycosylated markers. This goup joined forces to have pure reference compounds (and their isotopic analogues) synthesized for each of the markers in that list. This goal was achieved in December 2020. These analytical standards allow extremely reproducible quantitative results which are comparable between laboratories. ETS continues to offer analysis for these compounds in grapes, micro-ferments, and wines.
In a nutshell, the finalized Smoke Glycosylated markers panel includes, for each of the volatile markers listed in our Expanded Panel, its main respective glycosylated (sugar-bound) form – See figure 1. Note that glycosylated smoke-derived compounds are not contributed by toasted oak, making them particularly useful to assess wildfire impact in oaked wines. They are not directly odor-active, but may contribute lingering aftertastes often experienced with impacted wines. It is possible that they may hydrolyze in wine, slowly releasing volatile “free” forms and causing smoke flavors to become more noticeable with time. Several studies at ETS and elsewhere are investigating the actual extent of this mechanism in finished wines.
Volatile (“Free”) Markers
Glycosylated (“Bound") Forms
Guaiacol
Guaiacol Rutinoside
4-Methylguaiacol
4-Methylguaiacol Rutinoside
ortho-, meta- and para- Cresol
Cresol Rutinoside
Phenol
Phenol Rutinoside
Syringol
Syringol Gentiobioside
4-Methylsyringol
4-Methylsyringol Gentiobioside
Figure 1: Compounds included in the ETS Smoke Expanded Volatile Markers (left column) and their main glycosylated (sugar-bound) forms included in the Glycosylated Markers panel (right column). 34
WILDFIRE IMPACT
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Wildfire impact in grapes and wines is caused by a wide range of volatile phenols found in wildfire smoke. These compounds are absorbed and accumulate in berries. They eventually end up in wine where they can cause unwanted flavors. These off-flavors, described as “smoky”, “bacon”, “campfire” and “ashtray”, are usually long lasting and linger on the palate even after the wine is swallowed or spat out. Smoke impact in wine was identified as a serious problem after the 2003 wildfires in Australia and British Columbia. The California wine industry was also affected following the wildfires of summer 2008, and smoke impact has been a concern for many growers and wineries ever since. Here is a review of the various types of samples that may be submitted for testing:
1. Berries
2. Juices
4. Production Wines
During the 2008 California wildfires, ETS developed an analytical tool to screen grapes for the risk of smoke impact. This analysis measures trace levels of free guaiacol and 4-methylguaiacol in whole berries. Knowing the levels of these indicators in berries enables winemakers to assess the risk of smoke impact, and choose an appropriate course of action to mitigate the effects in their wines. Since 2021, an extended panel of volatile (free) smoke markers panel and a glycosylated markers panel have been available for berry samples.
It is possible to measure smoke taint markers in juice samples, but since smoke compounds are mostly located in skins, whole berry testing is the preferred method for preharvest screening. We do not accept fermenting samples, which may constitute a safety hazard.
Analyzing immediately after completion of primary fermentation allows a first assessment of wildfire impact in production wines. It is preferable to sample and analyze wines that have not come in contact with oak or oak-derived products, which can contribute volatile smoke markers.
Exposure of vines to wildfire smoke can widely vary within a small geographic area, depending mainly on proximity with the fires and wind conditions. Obtaining representative samples can be challenging. Mixing grape varieties in composite samples should be avoided, as grape cultivars often react differently to a similar exposure to smoke. Syrah grapes contain naturally occurring guaiacol and should never be mixed with grapes from other varieties. Submit 200 to 300 loose berries, keeping them cold and undamaged as much as possible (do not crush them). When shipping samples, use hard plastic containers with icepacks in an insulated package. Avoid submitting cluster samples, which trigger additional fees and may delay getting results. Berry samples are often requested by crop insurance providers, although micro-ferment samples are becoming more widely accepted. It is advisable to keep backup samples in a freezer.
3. Small Scale Fermentations (Micro-Ferments) In order to complement pre-harvest grape tests, wines from small-scale fermentations (“micro-ferments” or “bucket ferments”) may be tested for volatile smoke markers (basic or extended panels), and for glycosylated markers. The pros and cons of both tests are outlined in Figure 2.
With barreled wines, it is still possible to get useful information from the volatile markers by choosing the extended panel of volatile (free) smoke markers rather than the basic volatile marker panel (guaiacols only), and from taking samples from the most “neutral” barrels available. Keep in mind that there is no issue analyzing oaked wines for glycosylated markers, as oak or oak products do not contain these compounds. Analyzing for glycosylated markers in wine is always relevant regardless of contact with oak.
G r a p e S a mp l e s
M i c r o - fe r me nts
S a mp l e Pr e p a r at i o n Ti m e ( b e fo r e s e ndi ng t o t he l ab o r at o r y )
I m m e di at e
>1 We ek
S e ns o r y Ev a l u at i o n
N ot v e r y u s e fu l
U s e ful , but d ifficul t ( ne e d fo r mul tipl e t r a i ne d taste r s incl ud ing s e ns i t iv e ind iv idual s)
Ana l y s i s Tu r na r o u nd Ti m e
1 - 3 day s
1- 3 d ays
Pr e d i c t i o n o f S m o k e C ha r a c t e r s i n Pr o du c t i o n Wi ne s
I ndi r e c t ( v a r i ab l e “ mu l t i p l i e r s ” b et w e e n g r a p e a nd w i ne r e s u l t s )
R e d s : mo r e d ir e ct (but d e l aye d ) White s: unc e r tain ( f e r m e nt with skins fo r “ w o r s t case sc e nar i o ” ?)
Figure 2: Grape Samples vs. Small Scale Ferments (Micro-ferments) as pre-harvest testing options for wildfire smoke impact 36
Following the 2018 Mendocino Complex Fire Study (1), the selection of volatile (“free”) and glycosylated (“bound”) markers currently offered by ETS and the AWRI has shown to be relevant in the context of a major California wildfire event. Note the exception of volatile syringol and 4-methylsyringol, which (unlike in Australia) did not appear closely related to the level of exposure to wildfire smoke. The strength of correlations observed between markers, however, left the following question open: “Is testing for other markers than “free” guaiacol and 4-methylguaiacol really useful from a practical standpoint?” After measuring volatile markers (extended panel) and glycosylated markers for more than a year, we can answer that they definitely are useful. Here are results, typical and less typical, that we have observed with 2020 and 2021 wines.
Typical… and Less Typical Patterns To put it simply… when volatile markers are high, expect glycosylated markers to be also high. This is illustrated figure 3, which shows a range of levels observed in Cabernet Sauvignon wines, from normal low baseline levels observed without exposure to wildfire smoke, to extreme levels resulting from severe exposure. According to our observations so far, these patterns and ranges can be expected with most red wines, while levels in white and rosé wines are generally lower due to reduced skin contact. A notable exception is Syrah, now well known to contain naturally significant baseline levels of volatile guaiacol. With this variety however, baseline levels of other volatile markers appear to be normal, making them useful to assess smoke impact. Another oddity is Petit Verdot, which does not appear to contain naturally unusual baseline levels of smoke markers, but seems year after year to be much more sensitive to smoke. With Petit Verdot wines, the observed range is much larger than with any other variety: we have measured volatile guaiacol exceeding 200 ug/L, and combined levels of glycosylated markers approaching 1,000 ug/L. Less usual are patterns where volatile markers are relatively low, sometimes
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barely suggesting smoke impact or even no smoke impact at all, cooccurring with relatively high levels of glycosylated markers. We have observed such patterns in 2021 with California Sierra Foothills grapes and wines from Rhone varieties. These patterns are particularly worrisome to winemakers, due to the fact that glycosylated (bound) smoke compounds, which are odorless, are suspected to degrade with time, releasing volatile (free) odor-active compounds. Examples of such patterns are presented figure 3- three examples on the left. On the other hand, we have observed the opposite patterns, meaning high volatile markers but relatively low levels of glycosylated markers, with some regularity, especially with 2020 Pinot Noir wines – see figure 4 - two examples on the right. We do not know at this point if this is a recurrent occurrence with Pinot Noir, which might be observed year after year. Low levels of glycosylated markers may be caused by a weakened defense mechanism from the plant against smoke volatiles. This could be related to the severe heat wave experienced all across the Western United States in mid-August 2020, which often caused a slow or even “shut-down” metabolism with Pinot Noir grapes.
E X T E N DED VOLATIL E MA RKERS AN D GLYCOSYLATED M ARK E R S: WHAT LEVELS AND PATTERNS TO EXPECT IN WINES?
Figure 3: Range of volatile and glycosylated markers observed in 2020 Cabernet Sauvignon wines, from normal baseline to extreme levels resulting from severe exposure to wildfire smoke.
Figure 4: 2020 white and red wines from various grape varieties (Whites: CH = Chardonnay, CB = Chenin Blanc, Rosé: GR = Grenache, Reds: PN = Pinot Noir) displaying atypical patterns between volatile and glycosylated smoke markers. The three wines on the left have very low levels of volatile markers with high glycosylated markers, while the two wines on the right show opposite patterns.
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QUESTIONS & ANSWERS WILDFIRE IMPACT
I WANT TO TEST GRAPES FOR SMOKE, WHAT KIND OF SAMPLE SHOULD I BRING? The preferred sample for red or white grapes is a representative 200-300 loose berry sample, with berries as intact as possible. Transport in small rigid “sandwich boxes” works well – this is necessary if you are shipping samples. Avoid submitting cluster samples: the additional sample preparation time in the lab will delay results. We do not recommend submitting juice samples.
SHOULD I CRUSH BERRIES AND LET THEM SOAK IN THEIR JUICE BEFORE BRINGING THEM? We do not recommend doing so. When we have control of the sample preparation, our interpretation guidelines are more applicable.
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WITH WHITE GRAPES, SHOULDN’T I BRING JUICE SAMPLES? Since smoke compounds are mostly located in skins, we still prefer whole berry samples for white grapes. Our risk interpretation guidelines are similar for white and red grapes. Of course with white grapes, the risk of smoke characters materializing in wine can be mitigated to some degree by minimizing skin contact (with red grapes, making rosé by the direct pressing method can be a successful approach too), but in case of significant maceration with skins (e.g. following machine harvesting or intentional skin contact) the risk level may be equivalent.
CAN I MIX BERRIES FROM DIFFERENT VARIETIES AND BRING A COMPOSITE SAMPLE? This is not advisable, and even prohibited for samples submitted for insurance purposes. Over the years we’ve seen drastic differences in pick-up of smoke compounds between grape varieties. For example, Petit Verdot is often much more impacted than other Bordeaux cultivars. In 2020 we saw very substantial differences in behavior between Chardonnay and Pinot Noir.
CAN YOU TEST SYRAH GRAPES? Syrah naturally contains variable amounts of guaiacol, the main smoke marker. This makes it impossible to assess smoke impact based on guaiacol only, whether with grapes or micro-ferments. The only but very imperfect strategy available so far was to use other varieties grown next to Syrah blocks as “proxies”. Now the extended volatile and glycosylated markers panels help assessing directly Syrah samples.
CAN YOU TEST FOR MORE THAN JUST “FREE” GUAIACOLS (GUAIACOL AND 4-METHYLGUAIACOL)? Yes. We resumed offering our extended volatile (free) markers panel for wines in November 2020, and in December 2020 we offered an updated version of our glycosylated (bound) glycosylated markers panel. For the 2022 harvest, we will offer both tests for grapes, microferments, and production wines.
DOES ETS MEASURE “TOTAL” MARKERS, OR ALL FORMS OF “BOUND” MARKERS?
WHAT IS THIS UPDATED ANALYSIS FOR GLYCOSYLATED (“BOUND”) MARKERS AT ETS?
Q: I’D LIKE TO HAVE MICROFERMENTS TESTED. WILL ETS PREPARE THEM FOR ME?
Some laboratories offer testing after various acid and heat treatments, in an attempt to measure “Total” or “Bound” forms in their entirety. We have reservations about such tests and do not offer them. Instead, for each of the volatile markers listed in our Expanded Panel, we can measure directly by HLPC/MS/MS its main glycosylated (sugar-bound) form (see figure 1). This is the strategy also adopted by the Australian Wine Research Institute (AWRI).
ETS finalized in 2020 its own method for the determination of glycosylated (sugarbound) smoke markers, but quantitative results had to be expressed as “equivalent” ug/L units - a strategy commonly used when exact reference compounds are not available (e.g. with tannins commonly expressed as catechin or epicatechin equivalents). Following the 2020 firestorms, ETS joined resources with the AWRI and large wineries to have pure reference compounds synthesized, so that results can now be reported as “true” concentrations (see Fig. 5). Accurate, quantitative and reproducible results (comparable over a long period of time and between different laboratories) are now achievable and a reality at ETS.
We do not perform micro-ferments unfortunately. For guidance, we recommend scanning the QR codes on the next page which will direct you to protocols from UC Davis, Washington State University, and the AWRI. At completion of fermentation, transfer the fermented wine into a bottle, let settle in fridge for a few hours, decant and submit sample in a 60 mL plastic tube. If a crop insurance claim is considered, check with your insurance provider if they accept micro-ferments.
Q: WHEN IS THE BEST TIME TO BRING SAMPLES? For grape samples the typical recommendation is about 10-7 days prior to harvest. Keep in mind that the impact of smoke is cumulative and that “negative” results early in the season may give a false sense of security, especially if more exposure to smoke happens. Of course with micro-ferments several days need to be accounted for after grape sampling, in order to produce fermented samples that can be analyzed.
Figure 5: Glycosylated Smoke Markers and their isotopic analogues detected by LC/MS/MS (ETS Laboratories Dec 2020). These standards make quantitative, accurate and reproducible results (comparable over a long period of time and between different laboratories) possible. 40
A step-by-step procedure for smallscale fermentations (micro-ferments) is available on the UC Davis Website:
WILL YOU HELP ME WITH RESULTS INTERPRETATION? Of course. Although each fire event is unique, our interpretation guidelines based on volatile (free) guaiacol derived from our experience since 2008 have stood the test of time, and have proven to be quite robust (Fig.6). The presence of additional markers, with the extended volatiles marker panel, and the availability of a glycosylated markers panel, allow refining and confirming diagnostics. Always feel free give us a call for assistance with result interpretation.
The WSU Nano-Scale Fermentation Protocol:
The AWRI protocol is found at:
WHAT ARE NORMAL “BASELINE” LEVELS FOR VOLATILE EXTENDED AND GLYCOSYLATED MARKERS?
MY GRAPES (OR MICROFERMENTS) TESTED “POSITIVE”. SHOULD I HARVEST?
Grapes and wines naturally contain low “baseline” levels of smoke markers, variable by grape variety and possibly by geographic origin. In most cases, we are confident that our current knowledge is adequate to help our clients with result interpretation. Best, however, is to create your own database for grapes, microferments and/or wines from grapes not exposed to significant fire events. To help implementing such programs, ETS is offering grape testing for volatile and glycosylated markers in grapes at less than cost. Please refer to the details on the next page.
Our interpretation guidelines are related to incremental risk scales, as there is no “magic number” below which no risk is present and above which wines are guaranteed to be tainted. Choosing to harvest or not will always be complex risk management decisions, loaded with painful consequences for both growers and wineries. Analytical results only help in making these difficult decisions.
INTERPRETATION GUIDELINES FOR WHOLE BERRY TESTS (EXCLUDING SYRAH): ANTICIPATED RISK OF WILDFIRE IMPACT IN WINE LOW
MODERATE 0.5
HIGH
VERY HIGH
1.0
2.0
FREE GUAIACOL (ug/kg) INTERPRETATION GUIDELINES FOR MICROFERMENTS AND UNOAKED WINES (AGAIN EXCLUDING SYRAH):
UNLIKELY 1.0
2.0
POSSIBLE 3.0
LIKELY 4.0
MOST LIKELY 6.0
FREE GUAIACOL (ug/L) Figure 6: Interpretation guidelines for volatile (free) guaiacol, the main marker of wildfire smoke impact, in grapes and micro-ferments and unoaked wines. Additional markers in the extended volatile panel as well as glycosylated markers allow refining and confirming assessments.
THESE GUIDELINES ARE FOR GUAIACOL, NOT SUM OF TWO COMPOUNDS.GUIDELINES ARE SIMPLY OBSERVATIONS BASED UPON PAST EVENTS, AND MAY OR MAY NOT APPLY TO CURRENT OR FUTURE EVENTS.ETS DOES NOT, AND WILL NOT, PROPOSE ACCEPTANCE OR REJECTION CRITERIA 41
DOES ETS RECOMMEND KEEPING PRE-HARVEST BACKUP SAMPLES? Grape samples and micro-ferments serve two distinct purposes: helping with harvest decisions and serve as proof of smoke impact for insurance claims. Especially in the second case, it makes sense to keep backup samples, especially in the context of catastrophic wildfires.
WHAT IS YOUR TURNAROUND TIME? For the 2022 season, we have again expanded our GC/MS, GC/ MS/MS and LC/MS/MS analytical capabilities. Inclusive of added analytical equipment and method improvements, our current capacity is more than twice what it was entering the 2020 season. We have also solidified our partnerships with
international laboratories to provide surge capacity. For the most accurate turnaround time we recommend taking a look at our website (Analyses - Smoke Markers). In case of large fire events we’ll keep our TAT information for grape, microferment and wine tests prominently displayed and updated regularly.
WILDFIRE SMOKE GRAPE BERRIES IMPACT PROJECT In order to put wildfire smoke impact marker analyses into context, (particularly the glycosylated markers), ETS Laboratories has been building a database of naturally occurring concentrations over the past several years. This 2022 season
offers an excellent opportunity to expand this work since major winegrowing regions have, to date, largely been spared from widespread events such as those experienced in 2020. Only with a representative and robust database inclusive of the many
varietal and geographic combinations possible can analytical impact data be put in true perspective. ETS Laboratories is working to encourage sampling for this project by providing analyses at less than cost.
HERE IS AN OUTLINE OF THE PROGRAM:
•
200-250 berry representative samples taken after 18-20 brix
•
Fee per sample, only for this project, will be $365
•
Submit intact berries with minimal juicing ideally in rigid plastic containers such as disposable “sandwich boxes”
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Each sample will be identified with date sampled, varietal, and AVA data
•
Specific labels to identify samples as part of the program and to capture the required information are available directly from ETS or by client printing them from
•
Analysis will be performed for the extended volatile and glycosylated markers panels
a template which will be made available
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Do not submit samples where any wildfire impact is suspected
•
Samples for this project will be accepted until adequate quantities of data are accumulated or the first wildfire events impacting the region occur
PROJECT SPECIFIC LABELS ARE AVAILABLE AS WELL AS A TEMPLATE OF THE LABELS READY FOR THOSE WHO MAY WISH TO PRINT THEM THEMSELVES.
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H A RV E ST TO OL KI T
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GR A P E M AT U R I T Y MONITOR IN G PA N E LS The ETS Grape Maturity Monitoring Panels provide a set of analyses that growers and winemakers request to monitor fruit maturity, including Brix, Glucose + Fructose, TA, pH and malic acid, as well as berry size parameters and average sugar per berry. Monitoring sugar per berry allows growers to determine the duration and rate of active sugar loading, during which vines synthesize and actively transport sugar into berries. The time at which the sugar loading phase ends, and what level of Brix was achieved at that time, are both important indicators of wine growing conditions (excessive or insufficient vigor, water availability and resistance to heat stress). For more details see pg. 1
GR A P E P HE N O L I C S Follow changes in grape phenolics during ripening, using the catechin and tannin "ripeness" index to monitor seed ripening, and quercetin analysis to monitor canopy effects on grape phenolics.
E TS S CORP I ON S TM Wild yeast and bacteria from the vineyard may be introduced into the winery on the harvested fruit, causing spontaneous fermentation and/or spoilage. ScorpionsTM DNA analysis offers winemakers an early detection tool to identify these spoilage organisms. Despite the best practice of modern winemaking methods, microbial contamination often occurs during wine production. Spoilage microbes are capable of survival and growth in the wine, potentially producing offflavors, off aromas, and turbidity. Microbiological contamination is often undetected until related problems in the wine become noticeable by sensory evaluation. Scorpions™ assays, based on specific genetic targets, detect the full range of wine and juice spoilage organisms. This genetic analysis method detects microbial populations directly in wine or juice. Results are routinely reported within two business days, giving winemakers the ability to address problems before wine defects occur. Targeted genetic probes give the winemaker the ability to monitor only those specific spoilage organisms that have the potential to adversely impact wine quality, and to accurately measure populations down to extremely low levels.
GRAP E WAT ER CON TEN T Changes in grape water content influence finished wine composition and can be as important as standard sugar and acid measurements when making picking decisions. Grape water content is also very useful for understanding changes in TA, pH, ºBrix, and other harvest indicators.
HARV ES T JUICE PANEL Our most popular harvest panel offers a full range of grape and must analyses, combining more than 10 tests including fermentable sugar (to help estimate alcohol content) and YAN (yeast-assimilable nitrogen — to help predict sluggish or stuck fermentation and potential sulfide formation.) For more details see pg. 3
For more details see pg. 18
For more details see pg. 27 44
HARVEST TOOLKIT B OTRY TI S PANEL This comprehensive test panel checks grapes for Botrytis (using ScorpionsTM ) and laccase, detecting both the spoilage organism and its byproducts that can harm your wine.
G LU TAT HIO N E
M ON I TORI N G I B M P
Glutathione, a natural grape antioxidant, can protect the aroma and flavor of white and rosé wines and prevent premature aging. Glutathione levels fluctuate during production, as the compound can be absorbed by yeast and then released after fermentation.
The compound responsible for a "green bell pepper" aroma in wine, IBMP, decreases quickly during maturation. But once grapes are picked, it is hard to control. Monitoring changes in grape IBMP directly influences final levels in wine, and is crucial in making picking decisions.
For more details see pg. 31
For more details see pg. 32
W IL D FIR E IM PACT
E U CALY P TOL
The compounds in wildfire smoke are absorbed by vines and can cause unwanted flavors in wine. Analyzing for these compounds allows winemakers to screen grapes for the risk of smoke impact and work to mitigate its effects.
Eucalyptus character is a controversial sensory expression in red wines from California and countries with Mediterranean climates. Even a slight “eucalyptus” note can interfere with delicate varietal aromas, and can have a detrimental influence on certain grape varieties.
For more details see pg. 33
For more details see pg. 31 45
LACCAS E ACTIVITY Laccase is a polyphenol oxidase associated with rot caused by Botrytis. Elevated levels of laccase can result in oxidation of phenolic compounds that may cause color degradation or premature browning in red wines. In addition, laccase mediated oxidation can also affect the aroma profile of the wine.
Y EAS T V I ABILITY Our automated method reports yeast viability and total cell count back to the client within hours, and the real-time microscopic flow image analysis examines 1,000 times the volume used in standard microscopic methods, vastly increasing the accuracy of your results.
R A P ID P H E N O L I C S By the end of maceration or fermentation, the tannin content of a wine is already fixed. Monitoring phenolics during this critical period allows winemakers to better control tannins by increasing or decreasing phenolic extraction. For more details see pg. 29
DN A FINGER PR I N T I N G ETS Laboratories offers DNA fingerprinting to distinguish between closely related strains of Saccharomyces cerevisiae. ETS MLVA technology allows winemakers to monitor yeast population in native fermentations and check the efficiency of inoculations with commercial strains.
HARVEST RESOURCES
SINCE WE FIRST OPENED OUR DOORS IN ST. HELENA IN 1978, WE’VE GROWN ALONGSIDE THE WINE INDUSTRY, PARTNERING WITH OUR CLIENTS AS THEY’VE GONE ON TO CREATE MANY OF THE WORLD’S FINEST WINES. WE’RE CONTINUING TO INVEST NOT ONLY IN NAPA VALLEY, BUT ALSO IN OTHER RAPIDLY GROWING WINE REGIONS BY EXPANDING OUR LOCAL AND ONLINE SERVICES TO SUPPORT WINEMAKERS WITH ADVANCED TOOLS AND TECHNICAL ASSISTANCE. HERE’S WHAT TO TAKE ADVANTAGE OF IN HARVEST 2022:
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L O C A L J U I C E A N A LY S E S AT S AT E L L I T E L A B O R AT O R I E S Samples can be dropped off locally for any analysis ETS offers. These common harvest analyses will be run onsite for quicker turnaround.
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A L L S AT E L L I T E S
A N A LY S I S
TECHNIQUE
TURNAROUND
JUICE PANEL
MINERV A
SAME DAY
BUFFER CAPACITY
MANUAL
SAME DAY
ETHANOL
MINERV A
SAME DAY
FREE SO
FLOW INJ ECTION
SAME DAY
TOTAL SO
FLOW INJ ECTION
SAME DAY
TURBIDITY
TURBIDIMETRY
SAME DAY
VOLATILE ACIDITY
SEQUENTIAL ANALYZER
SAME DAY
GRAPE MATURITY MONITORING PANEL
V A RIOUS
SAME DAY
RAPID PHENOLIC PANEL
HPLC
1 DAY
GRAPE PHENOLIC PANEL
HPLC
1 DAY
SCORPIONS BACTERIA JUICE PANEL
SCORPIONS™
2 DAYS
SCORPIONS YEAST JUICE PANEL
SCORPIONS™
2 DAYS
SCORPIONS COMBINED JUICE PANEL
SCORPIONS™
2 DAYS
BRIX GLUCOSE + FRUCTOSE PH TA ( T ITRATABLE ACIDITY) TARTARIC ACID L-MALIC ACID POTASSIUM NOPA AMMONIA
PA S O R O B L E S , WA L L A WA L L A & NEWBERG
PA S O R O B L E S & NEWBERG
VISIT OUR WEBSITE FOR CURRENT PRICES, AND THE FULL LIST OF ONS I T E W I N E A N A LY S E S .
HANDLE WI TH
CA R E
It’s important to collect and handle harvest samples carefully to ensure accurate and representative results. We’ve collected our recommendations to help you get the most out of your harvest analyses.
JUICE SAMPLING Most harvest samples received at ETS come to the laboratory as juice. Berries pressed for a juice sample should be selected from at least 20-40 different clusters, and can easily be pressed by hand in their collection bag – pour the juice into a standard ETS 60mL sample tube and label with your ETS client labels. Samples should be kept cool to prevent fermentation.
GRAPE SAMPLING FOR PHENOLICS For grape phenolic testing, a representative sample is critical to obtain accurate results, especially in varietals with tight clusters. Samples for the Grape Phenolic Panel should include berries from at least 20-40 different clusters. Clusters can be collected either from harvest containers or directly from the vineyard. To get a representative sample, all the berries must be stripped from the clusters and mixed before bagging a 300-400 berry sample for analysis (about 500g or 16 oz). Samples should contain only intact and undamaged fruit to ensure accurate results.
BERRY SAMPLING Take 200-400 berries per block. Pick berries from random clusters on both sides of the row. Take berries from the top and bottom of both the front and back of each cluster. *Samples submitted for berry analysis should contain only intact and undamaged fruit.
We encourage clients to submit berry samples rather than whole clusters. If samples are submitted as clusters, ETS will prepare a berry sample for an additional fee.
LABELING Each bag of berries should be clearly labeled with the client name, sample ID, and analyses to be performed. ETS provides free sample labels that are pre-printed and barcoded with your client ID – visit our website, or give us a call.
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GEAR UP FOR HARVEST
Don’t get caught empty handed – order complimentary tubes, pre-printed labels, and shipping pods to take the headache out of collecting and shipping samples. 1. Login to your ETS account and select the winery you're ordering supplies for.
Outside the range of our sample pickup service? ETS offers free shipping kits, which include an insulated envelope and an ice pack, to help you easily send in samples no matter where you're located.
S H I PP I N G JU I CE S AM P LES F O R REGU LAR AN ALYS ES
S HI P P I N G JU ICE SAMPLES FOR S CORP I O N ANALYSIS
To prevent problems from fermentation, juice samples should be frozen or boiled for shipment, and clearly marked as either “FROZEN” or “BOILED” depending on the treatment used.
To ensure accurate results, it's important to avoid damaging DNA or killing yeast and bacteria:
Boiling 2. Use the "Get Supplies" button on the dashboard to place a supply order.
Boil samples with a loosely fitting cap to prevent evaporation and concentration. Do not over-boil.
° Keep samples cool with ice packs. Ship by overnight delivery using a °parcel carrier like FedEx, UPS, or GSO. Scorpions samples should not be frozen or boiled.
Freezing Freeze the sample in a plastic ETS sample tube. Do not over-fill the tube – leave a small space for the sample to expand when frozen. Never freeze samples in glass containers to prevent breakage and injury. 50
LOCATIONS & SERVICES IN ADDITION TO OUR ST. HELENA HEADQUARTERS, WE OPERATE SATELLITE LABORATORIES ACROSS THE WEST COAST TO BRING ADVANCED TOOLS TO WINEMAKERS' DOORSTEPS AND PROVIDE LOCAL SUPPORT TO OTHER GROWING WINE REGIONS. THESE QUICK GUIDES PROVIDE A REFERENCE FOR THE 2021 HARVEST, INCLUDING WEEKEND HOURS AND CONVENIENT SERVICES TO MAKE IT EASIER THAN EVER TO SEND IN HARVEST SAMPLES, INCLUDING DROPBOX LOCATIONS AND COMPLIMENTARY COURIER SERVICE. AS ALWAYS, IF YOU HAVE ANY QUESTIONS, JUST CALL YOUR LOCAL LAB AND WE'LL BE HAPPY TO HELP.
S T. H E L E N A C A L I F O R N I A
PHONE
(707) 963-4806 SHIPPING ADDRESS
A F T E R H O U R S D RO P B OX ST. HELENA Located at our laboratory, next to the main entrance.
COURIER SERVICE Our complimentary courier service is available in Napa, Sonoma, and Mendocino counties every day ETS is open.
Samples left overnight will be processed when we open the following business day. REQUEST A PICKUP
899 Adams Street, Suite A St. Helena, CA 94574
You can request a courier pickup by logging in to your ETS account, or by calling our lab.
SEE INSTRUCTIONS FOR SHIPPING JUICE SAMPLES – P. 41
DEADLINE
Please request a pickup by 10 am
HOURS Every Harvest ETS offers extended and weekend hours. Our team is on-call to meet your needs. Please check the ETS Website for our most up-to-date business hours.
To schedule on-call service, please call by 2pm on Friday: (707) 963-4806
This allows us to ensure speedy turnaround on time-critical harvest analyses. DROPBOX IS LOCKED F O R T H E P I N C O D E , C A L L U S , O R LO G I N TO YO U R E T S A C C O U N T A N D V I S I T “ C O N TA C T ”
For the most up-to-date dropbox hours and pick up times please check our website: www.etslabs.com/contact. LO D I D RO P B OX E S TAT E C R U S H
S O U T H N A PA D R O P B O X RUTHERFORD EQUIPMENT
2 W. Lockeford Street Lodi, CA
759 Technology Way Napa, CA
OPENING HOURS THE DROPBOX IS AVAILABLE WHEN E S TAT E C R U S H I S O P E N : ( 2 0 9 ) 3 6 8 - 7 5 9 5
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HEALDSBURG CALIFORNIA
PHONE
D R O P B O X L O C AT I O N S
(707) 433-7051
A F T E R H O U R S D RO P B OX HEALDSBURG
ADDRESS 190 Foss Creek Circle, Suite G Healdsburg, CA 95448
Located at our laboratory, on the north side of the building. Samples left overnight will be processed when we open the following business day.
Please check the ETS Website for our most up-to-date business hours.
You can request a courier pickup by logging in to your ETS account, or by calling our lab.
This allows us to ensure speedy turnaround on time-critical harvest analyses.
DROPBOX IS LOCKED. F O R T H E P I N C O D E , C A L L U S , O R LO G I N TO YO U R E T S A C C O U N T A N D V I S I T “ C O N TA C T ”
ENARTIS 7795 Bell Rd, Windsor, CA 95492 • S A M P L E S W I L L B E A C C E P T E D AT E N A R T I S A N D W I L L B E TA K E N TO E T S L A B O R ATO R I E S FOR TESTING. • PLEASE LEAVE SAMPLES BY 11 AM FOR S A M E - D AY S E R V I C E
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REQUEST A PICKUP
Please request a pickup by 10 am
SONOMA COUNTY
To schedule on-call service, please call by 2pm on Friday: (707) 963-4806
Our complimentary courier service is available in Napa, Sonoma, and Mendocino counties every day ETS is open.
DEADLINE
I F YO U N E E D TO S H I P S A M P L E S , P L E A S E S E N D T H E M D I R E C T LY T O O U R S T . H E L E N A LAB: 899 ADAMS STREET, SUITE A ST. HELENA, CA 94574
HOURS Every Harvest ETS offers extended and weekend hours. Our team is on-call to meet your needs.
COURIER SERVICE
PASO ROBLES
PHONE
(805) 434-9322
CALIFORNIA
A F T E R H O U R S D RO P B OX PASO ROBLES Located at our laboratory, next to the front door.
ADDRESS
Samples left overnight will be processed when we open the following business day.
3320 Ramada Drive, Suite B Paso Robles, CA 93446
COURIER SERVICE We're excited to offer complimentary courier service this September for our clients in the Central Coast. REQUEST A PICKUP
You can request a courier pickup by logging in to your ETS account, or by calling our Paso Robles lab. DEADLINE
Please request a pickup by 10 am. I F YO U N E E D TO S H I P S A M P L E S , P L E A S E S E N D T H E M D I R E C T LY T O O U R S T . H E L E N A LAB: 899 ADAMS STREET, SUITE A ST. HELENA, CA 94574
This allows us to ensure speedy turnaround on time-critical harvest analyses.
HOURS Every Harvest ETS offers extended and weekend hours. Our team is on-call to meet your needs. Please check the ETS Website for our most up-to-date business hours.
COURIER SERVICE SERVICE AREA DROPBOX IS LOCKED. F O R T H E P I N C O D E , C A L L U S , O R LO G I N TO YO U R E T S A C C O U N T A N D V I S I T “ C O N TA C T ”
D R O P B O X L O C AT I O N S
We're currently picking up samples in the Paso Robles and SLO areas. We will continue to expand as demand growsplease let us know if you'd like service.
CENTRAL COAST WINE SERVICES 2717 Aviation Way #101, Santa Maria, CA 93455
S T O L P M A N V I N E YA R D S 1700 Industrial Way, Lompoc, CA 93436
B U E L LTO N To schedule on-call service, please call by 2pm on Friday: (707) 963-4806
90 Easy St, Buellton, CA 93427 FOR ALL CENTRAL COAST DROPBOXES, PLEASE D R O P S A M P L E S B Y 1 1 : 0 0 A M F O R S A M E - D AY D E L I V E R Y M O N D AY - F R I D AY
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NEWBERG OREGON
PHONE
(503) 537-6245
A F T E R H O U R S D RO P B OX NEWBERG Located at our laboratory, next to the main entrance.
ADDRESS
Samples left overnight will be processed when we open the following business day.
COURIER SERVICE Our complimentary courier service is available in Salem, McMinnville, Newberg, and the surrounding areas every day ETS is scheduled to be open.
REQUEST A PICKUP
214 W. Hancock Street Newberg, OR 97132
You can request a courier pickup by logging in to your ETS account, or by calling our lab.
I F YO U N E E D TO S H I P S A M P L E S , P L E A S E S E N D T H E M D I R E C T LY T O O U R S T . H E L E N A LAB: 899 ADAMS STREET, SUITE A ST. HELENA, CA 94574
DEADLINE
Please request a pickup by 10 am This allows us to ensure speedy turnaround on time-critical harvest analyses.
HOURS Every Harvest ETS offers extended and weekend hours. Our team is on-call to meet your needs. Please check the ETS Website for our most up-to-date business hours.
DROPBOX IS LOCKED. F O R T H E P I N C O D E , C A L L U S , O R LO G I N TO YO U R E T S A C C O U N T A N D V I S I T “ C O N TA C T ”
ROS E B U RG D RO P B OX UMPQUA COMMUNITY COLLEGE
PICKUP TIME
Samples collected at 11:30 Monday – Thursday. Anything dropped off after 11:30am will be processed with the next pickup.
To schedule on-call service, please call by 2pm on Friday: (707) 963-4806
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912 Umpqua College Rd. Roseburg, OR
WALLA WALLA WASHINGTON
PHONE
ADDRESS
(509) 524-5182
3020 E. Isaacs Ave. Walla Walla, WA 99362
HOURS Every Harvest ETS offers extended and weekend hours. Our team is on-call to meet your needs. Please check the ETS Website for our most up-to-date business hours.
COURIER SERVICE
I F YO U N E E D TO S H I P S A M P L E S , P L E A S E S E N D T H E M D I R E C T LY T O O U R S T . H E L E N A L A B : 8 9 9 A D A M S STREET, SUITE A ST. HELENA, CA 94574
A F T E R H O U R S D RO P B OX WA L L A WA L L A Located at our laboratory, next to the main entrance. Samples left overnight will be processed when we open the following business day.
Our complimentary courier service is available in Walla Walla and the surrounding areas every day ETS is scheduled to be open. REQUEST A PICKUP
You can request a courier pickup by logging in to your ETS account, or by calling our lab.
DEADLINE
Please request a pickup by 10 am This allows us to ensure speedy turnaround on time-critical harvest analyses.
To schedule on-call service, please call by 2pm on Friday: (707) 963-4806
DROPBOX IS LOCKED. F O R T H E P I N C O D E , C A L L U S , O R LO G I N TO YO U R E T S A C C O U N T A N D V I S I T “ C O N TA C T ”
D R O P B O X L O C AT I O N S PROSSER
R E D M O U N TA I N COOPER WINE CO.
AUGUST-JANUARY
RICHLAND CENTRAL INDUSTRIAL SALES
WOODINVILLE W O O D I N V I L L E C U S TO M CRUSH
Dropbox
401 7th St. Prosser, WA
35306 N Sunset Rd. Benton City, WA
2235 Henderson Loop Richland, WA
14030 NE 145th St., Suite B Woodinville, WA
PICKUP TIME: 11AM
PICKUP TIME: 11:30 AM
PICKUP TIME: 12 PM
PICKUP TIME: 12:30
PLEASE DROP SAMPLES BY 10:30 A M F O R S A M E - D AY D E L I V E R Y M O N D AY - F R I D AY
PLEASE DROP SAMPLES BY 11 A M F O R S A M E - D AY D E L I V E R Y M O N D AY - F R I D AY
PLEASE DROP SAMPLES BY 11:30 A M F O R S A M E - D AY D E L I V E R Y M O N D AY - F R I D AY
PLEASE DROP SAMPLES BY 2 PM FOR OVERNIGHT SHIPMENT M O N D AY - F R I D AY
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