VOL. 2 / ISSUE 2
WINTER 2015
WINEMAKER’S Q UA RT E R LY PRESENTED BY ETS LABS
- F E AT U R E HARVEST 2015: AN OVERVIEW -IN THE LAB TCA AND HALOANISOLES -COME SEE US TRADESHOWS AND SEMINARS
TABLE OF CONTENTS VOL. 2 ISSUE 2
WINTER 2015
4
Questions and Answers
7
TCA: Where are We Now?
9
Harvest in Review
14
Sensory Table
15
Calendar of Events
Editorial Team:
Owners: Gordon Burns, Marjorie Burns Creative Direction: Evin Morrison
Photography: Kingsley Burns, Evin Morrison
Editorial Contributors: Rich DeScenzo, Steve Price, Eric Herve, Gordon Burns, Marjorie Burns
Questions or feedback? Send us a note: editor@etslabs.com
H
arvest is behind us, but we know that doesn’t mean that your work crafting fine wines is over.
Clarification of cellared wines continues with bottling season just ahead and our ETS team is ready to assist you in any way possible. Our team has compiled and analyzed the data from Harvest 2015. This was an interesting vintage and we are excited to share the trends we saw with you on page 9. Sensory taints in wines can occur during production and aging due to a wide variety of factors. We’ve formed a list of some
of the most common odors found in wine and shared possible causes on page 14. We are pleased to see many of our clients as often as daily at our laboratories up and down the west coast. For those of you unable to make it to the labs, we hope to see you soon at one of our upcoming seminars or at tradeshows. Find our spring event calendar on page 15, and stop in so we can say hello! We are excited to continue our partnership with you and your winemaking team and look forward to working with you throughout the upcoming year. Gordon Burns (707) 302-1211 gburns@etslabs.com
Marjorie Burns (707) 302-1222 mburns@etslabs.com ETSLABS.COM
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QA &
What is this I hear about allergens?
Allergens can potentially pose a health risk to a very small group of sensitive individuals. OIV (The International Organisation of Vine and Wine) regulations regarding mandatory labeling of wines containing allergens have been in place for several years, in addition to regulations existing in various non-European countries. The use of allergen-containing products in the winemaking process creates a very minor potential for allergen residue in finished wines. Despite facts regarding the fate of these fining agents during the winemaking process, and studies demonstrating the very low risk of such residues, winemakers need to be aware of the regulatory issues involved. Casein is a protein found in milk and milk products that has been identified as a potential allergen. Several commercial products used for fining wines contain milk products and/or casein. The milk protein-containing products are primarily used to bind to and remove tannins. Ovalbumin is the primary protein found in eggs and egg products, and has been identified as a potential allergen. Several commercial fining products for wines utilize egg products and may contain ovalbumin. The egg proteincontaining products are primarily used to bind to and remove tannins. Lysozyme is a protein derived from eggs and has been identified as a potential allergen. Several commercial fining products for wines utilize lysozyme. Lysozyme-containing products are primarily used to remove lactic acid bacteria. Isinglass and fish gelatin are protein-based fining products made from fish swim bladders. Fish contain a class of proteins called parvalbumins that can cause an allergic response in sensitive individuals. Wines fined with Isinglass or fish gelatin products could potentially contain small amounts of allergens. Gluten is found in wheat-based products and contains several proteins which have been identified as potential allergens. A paste made from wheat flour, which contains gluten, is sometimes used by cooperages to form a seal between the heads and staves of oak barrels. Wine aged in these barrels could potentially contact the wheat paste, resulting in low levels of gluten in the wine. Gluten allergen testing is currently not mandatory for wine unless the bottle label makes claims that the wine is gluten-free.
4 |WINEMAKER’S QUARTERLY
What microbes are really driving my winemaking?
ETS Laboratories utilizes a method of DNA fingerprinting known as MLVA (Multi-Locus Variable Copy Number Tandem Repeat Analysis), to discriminate between closely related strains of both Saccharomyces cerevisiae and Oenococcus oeni. This method looks at targeted areas of the genome to differentiate individual stains of the same species from one another. This data enables winemakers to detect and identify commercial strains of Saccharomyces cerevisiae and Oenococcus oeni and unique non-commercial strains that may be present in their wine. Our DNA fingerprint analysis for Saccharomyces cerevisiae is useful for monitoring yeast populations in native fermentations, as well as determining the efficacy of inoculations with commercial strains. Results from several native fermentation analyses have shown that commercial strains of yeast previously used at a winery were in fact the dominant yeast strains recovered from the uninoculated (“native”) fermentations conducted in those wineries. Wineries have also used the DNA fingerprinting to measure the success of malolactic inoculations with Oenococcus oeni. Commercial strains of Oenoccoccus are generally screened by manufacturers to select strains that are not producers of biogenic amines such as Putrescine, Cadaverine, and Histamine that are often associated with wild strain fermantations. DNA fingerprinting allows winemakers to determine if the bacterial strain driving their malolactic fermentation is actually the commercial strain of Oenococcus oeni added to the wine or an indigenous or potentially problematic wild strain of lactic acid bacteria. ETS DNA fingerprinting analysis allows winemakers to monitor Saccharomyces cerevisiae and Oenococcus oeni populations in their fermentations. Monitoring ensures that process decisions affecting wine production are made based on actual data from the winery’s fermentation. Results can also be used as a quality control tool to verify that desired strains are dominating the individual fermentations.
Is volatile acidity good or bad?
Volatile acidity in wine refers primarily to acetic acid, although it is often associated with ethyl acetate from a sensory point of view. Volatile acidity is an important component in wine, with many people believing that a small controlled amount is normal and makes a necessary contribution to a wine’s flavor and aroma profile. Different wine styles can mask, or not mask, the same levels of volatile acidity. There is a fine line between complexity and spoilage, but most winemakers agree that excessive levels of acetic acid are detrimental to wine quality. Volatile acidity is produced by both yeast and bacteria, although excessive levels are more often associated with bacterial contamination during the winemaking process. Volatile acidity can originate and be produced in grapes in the vineyard, during cold soak with red wines, during primary fermentation, post malolactic fermentation and during barrel aging. Although the primary culprits blamed for acetic acid production are often the acetic acid bacteria, various heterofermentative lactic acid bacteria can also contribute significant levels of acetic acid, especially in stuck fermentations. The best way to minimize volatile acidity production is to understand the mechanism of its formation at the different time points in the wine production process. Eliminating the conditions conducive to formation of volatile acidity after malolactic fermentation and during barrel aging will help ensure overall lower levels of volatile acidity in wines. Sanitation, monitoring of microbial populations, SO2 management, and barrel headspace management are the primary tools winemakers use to prevent formation of excessive volatile acidity in their wines.
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6 |WINEMAKER’S QUARTERLY
TC
CA
Don’t we all miss the late 90’s, when TCA (Trichloroanisole) was still synonymous with cork taint? Systemic winery contaminations were unheard of, and other
haloanisoles like TeCA (Tetrachloroanisole) and PCA (Pentachloroanisole),
while wreaking havoc in some parts of Europe, seemed a distant menace.
S
ince then, the haloanisoles issue has increased in complexity and new threats have emerged.
In the early 2000s, while the Cork Quality Council and ETS were busy fighting cork taint, it appeared that some wines were being contaminated by TCA long before bottling. During our investigations of the first cases of TCA “outbreaks”, it became clear that the common practice of bleach sanitation resulted in buildup of trichlorophenol (TCP) in wineries. TCP is TCA’s direct precursor. This molecule can remain “dormant” for decades, lurking in wood, lumber, timber, structures, and even on floors and in walls. TCA cellar outbreaks follow increases in microbial activity (usually triggered by higher humidity) as molds and soil bacteria try to convert TCP, which is highly toxic to them, into less toxic compounds. Wine can be tainted by contact with bleach-sanitized winery equipment such as hoses or resin-lined tanks. TCA also easily becomes airborne, making air a vector of contamination, since wine absorbs airborne TCA. Winemaking equipment or ingredients stored in contaminated areas may also absorb airborne TCA, which later can be extracted by contact with wine during the production process. In recent years, we have discovered that even grapes can be tainted by TCA. Such contaminations have been traced to a vineyard pesticide, and also the use of bleach to prevent biofilm buildups in overhead sprinkler systems. Unfortunately, another potential source of TCA wine contamination is new cooperage. The origins of this problem are not yet fully understood and need further study
TCA’s “little brothers”: TeCA, PCA and TBA
TeCA and PCA in wine originate from Pentachlorophenol-based wood preservatives, widely used during the 1970s and early 1980s. These wood preservatives contain both PCP (Pentachlorophenol) and TeCP (Tetrachlorophenol). PCP and TeCP are chemically stable, but can be degraded by molds and soil bacteria into TeCA and PCA, the very same way that TCP can be transformed into TCA.
TBA (Tribromoanisole) often originates from pallets treated with TBP (Tribromophenol), a wood preservative widely used in South America. TBP-treated wooden container floors are another culprit, occasionally tainting shipments of barrels or other winemaking supplies. Beware of a TCA-like, musty/moldy odor, with a briny seaweed character, on shrink wraps! TBA can also be traced to brominated flame retardants that are often used in insulation materials, electrical equipment, and HVAC units. This latter origin seems more common in newer facilities.
Where are we now? The fight against cork taint is a success story. The ETS Releasable TCA test has been implemented by major cork suppliers worldwide. Testing occurs at all stages of the production process, with ETS performing final checks on cork bales arriving in the US. The Cork Quality Council can claim that cork releasable TCA levels in the US market are now 95% lower compared to 2001. US wineries are seeing the benefits, as cork taint is now widely considered to be under control. While sanitation practices have changed, the legacy of bleach survives, and airborne TCA is often detectable in wineries. This is also true for TeCA and PCA in wineries built before the 1990s, which often contain PCPtreated lumber. Fortunately, large-scale wine contaminations are less frequent, as wineries are often aware of the problem and monitor atmospheric haloanisoles regularly. TBA, on the other hand, seems to find its way into wines more frequently. Finding new barrels occasionally contaminated by TCA is not a new phenomenon, but one that has gained attention in recent years. In response, ETS now offers a variety of tests based on detection by “Triple Quad” Mass Spectrometry, as the performance of regular Mass Spectrometry is not sensitive enough for analysis of haloanisoles in cooperage oak. As wine consumers become ever more sophisticated, they also become more discriminating. Traces of haloanisoles that wouldn’t have had serious consequences in the past can now lead to commercial failures. At ETS, we continue to offer even more sophisticated tools to help our clients protect their wines and deliver sound products to the marketplace. ETSLABS.COM|
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8 |WINEMAKER’S QUARTERLY
HARVEST
2015 The raw materials that Mother
Nature provides winemakers are different each vintage
It all begins with your juice. Analysis of juice components provides important information about each vintage’s juice composition, helping winemakers to predict future wine attributes such as final alcohol, pH, and TA, and to craft better wines from each year’s fruit. This data is especially useful if taken in the context of past vintages. Comparison with wines from past vintages is one of the ways we often evaluate the current vintage. Comparing juice parameters from vintage to vintage provides a great tool for predicting wine chemistry and making adjustments to winemaking practices if required. The ETS Juice Chemistry Panel is a comprehensive panel that provides information about nitrogen balance (YAN, NOPA, Ammonia), sugar (Brix, Glucose+Fructose), acid balance (pH, Titratable Acidity, Malic acid, Tartaric acid), and Potassium. YAN, NOPA, and Ammonia are not only critical for optimal fermentation but can also influence growth of spoilage microbes. Ammonia is an easily assimilated form of nitrogen rapidly used by microbes, while NOPA is more like a time-release form of nitrogen, requiring more effort for the microbes to
assimilate. Sugar levels are critical in determining the final alcohol level in the wine, and elevated levels may require adjustments to avoid difficulties at the end of fermentation. Finally, the juice components affecting wine acid balance provide information on everything from shifts in pH during malolactic fermentation to final wine titratable acidity, and even information on potential issues with cold stabilization of the wine.
Over the past few years we have looked at the juice panel data for all samples from a particular state, averaging them to obtain a “global” look at nitrogen status, sugar levels and acid balance. The global data is derived from as many as tens of thousands of samples depending on the location. Looking at Figure 1, we see trends indicating increased YAN and potassium levels in the California 2015 vintage as compared to the 2014 vintage. Although the global data provides an interesting overview of trends for the vintage, looking at varietal-specific data can provide information that might be more useful for understanding what occurred during the 2015 vintage. The individual varietal data presented is a subset of the 2015 vintage data and selected based upon demographics available to us. Samples with ambiguous demographics were not used in the vintage analysis.
Figure 1. Global juice panel data averages for the 2011-2015 vintages.
Brix
Glu/Fru (g/L)
pH
TA (g/L)
Malic (g/L)
Tartaric Potassium Ammonia (g/L) (mg/L) (mg/L)
NOPA (mg/L)
YAN (mg/L)
2015
25.4
272
3.63
5.2
2.3
4.6
1793
75
120
181
2014
25.2
268
3.67
4.9
2.1
4.9
1682
66
113
165
2013
25.7
274
3.67
4.9
2.2
4.3
1742
57
120
165
2012
24.5
261
3.64
5.3
2.4
4.4
1715
54
113
148
2011
23.6
254
3.57
5.9
2.5
4.5
1638
85
140
210
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JUICE NITROGEN STATUS
Global YAN increased in 2015 by almost 10%, driven by a 14% increase in ammonia and a 6% increase in NOPA. The 2015 vintage saw YAN increases in white varietals from 10-30% (Figure 2). Likewise red varietals saw an increase from 10-20% (Figure 2). Increased YAN,
primarily due to increased ammonia in 2015 could have resulted in faster fermentation starts and/or accelerated growth of indigenous microbes during cold soak. If you were monitoring YANs this year, you probably supplemented with less nitrogen than in 2014.
2015 CA YAN
2015 CA Ammonia
2015-2014 YAN Differences
2015-2014 YAN Differences
Figure 2. YAN values for both red and white varietals in the 2015 vintage. The red line indicates the 2015 vintage global average for YAN values.
JUICE ACID CHEMISTRY
Acid balance in wine is based on the levels of tartaric acid, malic acid, and potassium, which determine the pH and titratable acidity of the juice. These important parameters are impacted by both viticultural practice and vintage. Overall, pH was down slightly for red and white varietals in
2015 CA pH
the 2015 vintage compared to 2014 (Figure 4). Juice pH for many of the red varietals was in excess of pH 3.7 and combined with increased malic acid in the 2015 vintage, indicates a potential for higher pH values post malolactic fermentation.
2015 CA pH
Figure 4. Summary of pH values for 2015 vintage and comparisons with the 2014 vintage
10 | WINEMAKER’S QUARTERLY
JUICE SUGAR STATUS
Vintage and viticulture practice impact ripening. With that said, sugar levels still play a big role in picking decisions, and for that reason it is not surprising to see relatively insignificant changes in the sugar levels from vintage to vintage. As expected, brix levels for white varietals were significantly lower than red varietals. Zinfandel and Cabernet Sauvignon
2015 CA Brix
2015-2014 Brix Differences
averaged over 26.5 brix in the 2015 vintage. Glucose/Fructose levels for Cabernet sauvignon and Zinfandel both averaged over 290 g/L which provides sufficient sugar to produce in excess of 17% ethanol. No major trends were observed in brix levels for different varietals between 2015 and 2014.
2015 CA Brix
2015-2014 Brix Differences
Figure 3. Brix values for both red and white varietals in the 2015 vintage. The red line indicates the 2015 vintage global average for Brix values.
2015-2014 pH Differences
2015-2014 pH Differences
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Titratable acidity measures the free, or available, acid groups in a wine and provides a good measure of acid perception. Titratable acidity values for the 2015 vintage averaged higher in both red and white varietals
2015-2014 Titratable Acidity Differences
(Figure 5). Changes in titratable acidity are usually related to changes in pH, and that is what we observed this year.
2015-2014 Titratable Acidity Differences
Figure 5. Comparison of titratable acidity values for the 2015 and 2014 vintages Potassium levels in juice and wine influence pH, titratable acidity, and levels of potassium bitartrate formation. Overall, potassium levels were higher in the 2015 vintage as compared to 2014 (Figure 6). Differences in
2015-2014 Potassium Differences
Potassium values show an inverse trend as compared to differences in pH values for the 2015 and 2014 vintages. Higher levels of potassium and tartrate in 2015 can impact cold stabilization of wines.
2015-2014 Potassium Differences
Figure 6. Comparison of potassium values for the 2015 and 2014 vintages Individual juice chemistry parameters can change significantly from vintage to vintage. Knowing what these changes are and comparing them with previous vintages can provide winemakers with a better
12 | WINEMAKER’S QUARTERLY
understanding of what they face in the current vintage. It is often easier, better, and less stressful to make proactive, data-driven decisions rather than to react to surprises during the winemaking process.
CERTIFICATES OF ANALYSIS FOR WINE EXPORT “They want what?” Demands for lab reports (Certificates of Analysis) accompanying international wine shipments have run amok! An ever-expanding list of countries and importers are demanding an ever-expanding list of analyses in order to allow consignments of wine large and small access across their borders and into their distribution chains. Most of these demands are nothing more than what are properly referred to in the international community as “Non-Tariff Trade Barriers”. In our opinion, the only legitimate analytical requests are to assure that the products pose no risk to the health and safety of the consumer, and to assure that they are classified correctly for taxation purposes. Wine is an inherently safe product and yet, currently in nearly every economy, certificates of analysis are required at some point in the trade process. Efforts by local and international organizations such as the World Wine Trade Group, The International Wine Technical Group and The California Wine Institute have intensified over the past decade in an effort to reduce or eliminate all forms of such trade barriers.
ETS Laboratories is a member of the Paris based organization known as FIVS (Fédération Internationale des Vins et Spiritueux), FIVS is a worldwide trade federation serving the global alcohol beverage industry that has been working since 1951 to promote an environment free from trade-distorting factors of all kinds. ETS participates in international FIVS meetings, and serves on committees and working groups within FIVS striving to eliminate or reduce export analytical requirements on behalf of our clients. Regardless of our success in reducing and rationalizing requirements, however, there will inevitably remain some need for analyses in international trade where there is a justifiable or science-based reason. When you must provide analyses for export, ETS is fully equipped to provide the analyses you need under the internationally accepted laboratory standard of ISO 17025. Very importantly, our continuous international exposure will allow ETS to help you in choosing the minimum list of analyses appropriate for your wine’s destination and help keep your costs under control.
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13
What’s that
odor?
From vineyard to aging in bottle, sources of off-odors in wines are multiple and sometimes difficult to identify. Here’s a list of “problem” odor compounds, with their indicative sensory thresholds and origins. Start
Green Bell Pepper IBMP (3-ISOBUTYL-2-METHOXYPYRAZINE)
10-15 ng/L
Problematic grape ripening, usually with Cabernet
(ppt)
Rotten Eggs, “Reduction” HYDROGEN SULFIDE (H2S) AND MERCAPTANS Problematic primary fermentations, compacted lees, (ppb) lack of oxygen, bottle aging.
1 μg/L
Eucalyptus
Cooked Vegetables, Canned Corn
EUCALYPTOL (1,8-CINEOLE)
DISULFIDES (DMDS, DEDS) AND DIMETHYLSULFIDE (DMS)
1.5 - 3.5 μg/L (ppb)
Eucalyptus trees next to vineyards
Smoke Taint GUAIACOL AND 4-METHYLGUAIACOL Wildfires
4-6 μg/L
(ppb) of Guaiacol
10-20 μg/L (ppb)
Excessive aeration following H2S/Mercaptans problems, on-lees aging, bottle aging.
Buttery, Popcorn DIACETYL Malolactic fermentation
0.3 - 3 mg/L (ppm)
Earthy, Beetroot
“Brett”, Barnyard
GEOSMIN
4-ETHYLPHENOL (4EP) AND 4-ETHYLGUAIACOL (4EG)
40-50 ng/L
Moldy grapes, barrels
(ppb)
(ppt)
Solvent, Nail Polish ETHYL ACETATE
150-200 mg/L (ppm)
400 μg/L for 4EP
Non-saccharomyces “wild” yeasts and acetic bacteria.
Brettanomyces yeast during winemaking or aging
“Aldehydic”, Overripe Apple (whites), Chocolate (reds) Acetaldehyde
100 mg/L (ppm)
Inadequate protection from oxygen during winemaking or aging.
Vinegar, Volatile Acidity (VA)
Mousy, Corn Chips
ACETIC ACID
2-ACETYLTETRAHYDROPYRIDINE, 2-ETHYLTETRAHYDROPYRIDINE, 2-ACETYL-1-PYRROLINE
0.6-0.9 g/L
Acetic bacteria. Malolactic bacteria when malolactic fermentation is completed in presence of residual sugars.
4-18 μg/L (ppb)
Mostly attributed to Lactobacillus brevis/ fermentum/hilgardii bacteria.
If you ever have any questions about sensory issues please contact Eric Herve at 1 (707) 302-1227. 14 | WINEMAKER’S QUARTERLY
EVENTS
MARC H 15 TUES 16 WED
Paso Robles, CA
Come see our team at the WIVI Central Coast Symposium as we introduce our new location! Booth #322
APR I L 07THURS
Paso Robles, CA
27 WED
St. Helena, CA
We are excited to announce the official opening party of our Paso Robles Location. Please join us and Scott Labs to celebrate this new resource for the Central Coast wine community.
M AY 03 TUES
Walla Walla, WA
Join us at Walla Walla Community College for Dr. Rich DeScenzo’s seminar on barrel sanitation. The seminar will run from 9-11 AM
Join us in the CIA Barrel Room for the Wines and Vines Oak Conference. Come check out interactive setup with Dr. Eric Herve. Booth # 20
For more information and a full list of our events, visit our website: etslabs.com/seminars ETSLABS.COM |
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