VOL. 1 / ISSUE 3
SPRING / SUMMER 2015
WINEMAKER’S Q UA RT E R LY PRESENTED BY ETS LABS
- F E AT U R E Using Phenolics to Drive Style -JUICE PANELS Utilizing Data and Adjusting Juice - N E W AT E T S Expanding Our Services
TABLE OF CONTENTS VOL. 1 ISSUE 3 5
Summer 2015
Juice Chemistry
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Your Questions Answered
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Utilizing Phenolics
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Expanding Our Services
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Our New Locations
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
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t’s not too early to be thinking about the upcoming harvest and planning strategies for dealing with any vintage specific issues. Year to year variation in fruit composition affects winemaking practice such as juice adjustments (pg 5) and influences wine style decisions. Likewise, phenolic levels which also play a critical role in wine style and sensory perception may be monitored and modified to meet your winery’s target. We discuss the source and role tannins play on page 8. We are pleased to announce the expansion of our services in California, Oregon and Washington. Due to the support ETS has received from all of our customers, we are adding new analytical
technologies to our existing Satellite lab locations and opening a new facility in Paso Robles to better serve our Central Coast clients. More information and details about our extended service and new locations are on pages 13-15. Thank you for your support in making these expansions and enhancements a reality. The entire ETS staff is dedicated to helping you achieve success. We look forward to working in partnership with you this upcoming harvest and throughout the year as you continue to craft and create world class and award winning wines.
Gordon Burns (707) 302-1211 gburns@etslabs.com
Marjorie Burns (707) 302-1222 mburns@etslabs.com
Understanding Your Juice WHAT DOES THE ETS JUICE PANEL TELL ME The most frequently submitted samples for juice chemistry analysis are samples of free run juice, or grapes/clusters that are crushed by hand, resulting in free run juice for analysis. Analysis on free run juice provides data that allows the winemaker to identify if there is anything unusual about the current vintage and to compare composition differences from vintage to vintage. These comparisons enable the winemaker to observe significant increases or decreases in parameters such as YAN, TA, pH, K+, and tartaric acid in their juice, and make adjustments prior to fermentation. Clients sometimes ask why they see a difference in the concentration of acids, sugars, or alcohol potential between the free run juice and mid-to end stage fermentation sample results. Differences between the two are often due to sampling and processing. The free-run juices obtained by crushing grape cluster samples may not reflect the actual content of some juice components such as acids and potassium, since they can initially be sequestered at high levels in grape tissue adjacent to the skin. As the grape tissue breaks down during the initial fermentation stages, 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 not release initially, providing an underestimate of total sugar and potential alcohol.
It is also not uncommon 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 as well as how thoroughly each sample is crushed and mixed. All of these factors can contribute to the differences observed between the initial free run juice and the final pH, TA and ethanol in the wine. Winemakers who are targeting a certain TA and pH, or ethanol level often check their juice chemistry again at the fermentation midpoint.as the must components are in a state of flux throughout the alcoholic fermentation to post-malolactic fermentation. Many prefer to make incremental adjustments rather than rely on one initial or massive adjustment. These mid-point numbers are used to make ongoing and final fermentation adjustments, enabling better achievement of their target goals. 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 with the fermentation process stage. The use of small, incremental fermentation adjustments helps provide a more controlled outcome in regards to pH, TA and final ethanol content.
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QUESTIONS ANSWERS We have compiled some of the most frequently asked questions we get before harvest in the lab and answered them for you here.
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Last year my Scorpion tests showed high levels of wild yeast. Could that be a problem? What should I look for this year? The wild yeasts Hanseniaspora and Pichia are often found in must, and can present problems during the cold soak process, or during the early stages of fermentation. Problems associated with these wild yeast strains include production of ethyl acetate, acetic acid, and acetaldehyde. Elevated levels of these wild yeasts prior to addition of a commercial yeast strain are a forerunner of potential nitrogen deficiencies during fermentation. These indigenous yeast strains can utilize the yeast assimilable nitrogen (YAN) in the must leaving low, to no YAN available for the winery’s inoculated commercial Saccharomyces cerevisiae strain. Analyzing the must for YAN before your yeast addition provides the baseline nitrogen level available for utilization by Saccharomyces cerevisiae during fermentation. This information can be used to implement an effective nitrogen supplementation plan for fermentation. Problematic fermentations due to YAN deficiencies can be minimized by knowing which microbes are present and competing for nitrogen in the must, and the level of nitrogen available at the start of fermentation.
Q:
What cold stability test should I run if I am using carboxymethyl cellulose (CMC) or other additive technologies? There are an increasing number of wineries using additive technologies such as carboxymethyl cellulose or mannoprotein preparations to ensure cold stability in their wines. These products enable wineries to cold stabilize wines without the high energy costs associated with traditional refrigeration stabilization. Standard methods for determining cold stability, such as potassium concentration product and modified mini-contact conductivity analyses are not appropriate when additive technologies have been used to cold stabilize the wine. Many of our clients request the DIT conductivity test to determine if their wine is a suitable candidate for cold stabilization using CMC or other additive treatments.
A: Q: A:
ETS recommends that you contact your preferred vendor as each manufacturer has their own use criteria for cold stabilization products. Your vendor should be able to recommend what test to run and interpret the results/values to see if they consider your wine a suitable candidate for use of their cold stabilization additive technology products. Once the wine has been treated, many of our clients request the ISTC50 conductivity test to determine if the additive treatment succeeded in cold stabilizing their wine. Once again, we recommend you contact your preferred vendor as each manufacturer has their own validation criteria for treatment efficacy of their particular product.
Why don’t my total organic acids add up to or equal my TA number? Your total acids do not equal your TA number because they are not the same thing. “TA” is a measure of titratable acidity, not the amount of total acid present and the two numbers are very distinctly different. Titratable Acid represents the total amount of protons available to bind to OH- groups or a measure of all available hydrogen ions in solution. In the USA it is expressed in juice or wine as tartaric acid equivalents. The titratable acidity of grape juice, like most fruit juices, is always less than the total acidity number representing the total organic acid concentrations. The number of hydrogen ions recovered from a juice is typically only 70 to 80% of those expected from the analytical tartaric and malic acid concentrations because some of the hydrogen ions from the acids have dissociated and been replaced/substituted by other cations such as K+ and Na+. Titratable acidity provides a good measurement of “perceived acidity” when tasting the wine. Total Acid is the total amount of organic acids in a juice or wine. Grape juice typically contains major amounts of tartaric and malic acid, with very small concentrations of citric acid. In addition to the tartaric, malic and citric acid found in juice, wine may also contain lactic, succinic and acetic acids.
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WHY
PHENOLICS?
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Different wines with a wide range of styles can be made from the same grapes. For example, Cabernet Sauvignon grapes can make wines of considerable structure and aging potential, or the same grapes can make a delicate rosĂŠ. A red Pinot noir wine can range from rich, full and developed to young, crisp and fruity with the differences due to decisions made by the winemaking team.
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ften style differences start in the vineyard with grape production targeting a specific wine type, but the realization of that style happens in the winery.
Phenolic composition is a significant part of wine style. Tannin in particular can dominate the sensory impression of a wine affecting both color and mouthfeel. The total amount of tannin has by far the greatest effect on style, but the tannin characteristics are also significant. Does the tannin come from predominantly skins or seeds? Has the tannin been modified? Is it fixing color components? Dealing with tannin amount and tannin qualities is the responsibility of winemakers. Their successful control of these variables is required to make a wine of a desired style. In many ways this process is an art as the winemaker must balance phenolic composition with other critical style components such as alcohol, acidity and aroma. Sensory evaluation has for many years been the only readily available tool to support this art. Today, winemakers are increasingly using advanced analytical information to help make and validate sensory decisions. >> continue ETSLABS.COM|
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Grape Composition Phenolic composition of grapes is set at harvest. The quantity and quality of the phenolics has largely been determined by the site and viticultural practices. Grape phenolics, however, change rapidly during the last few weeks of ripening, and the timing of harvest is often one of the most important style decisions made by the winemaker. Potential tannin, seed ripeness, tannin modification and anthocyanin content change with ripening and vary between grape blocks. The concentration and characteristics of phenolics and their changes during ripening can be measured with the ETS Grape Phenolic Panel. In addition to phenolic changes, the amount of water in grapes is in flux during ripening. The amount of water in grapes strongly influences concentration of all the phenolic compounds and can be measured with grape water content. From a style perspective, the first concern is concentration. Are phenolic concentrations low or high, and how much are they being diluted or concentrated by grape water? Total anthocyanin content is an excellent indicator of phenolic potential. Higher anthocyanins are correlated with higher tannin in wines, and anthocyanins appear to influence tannin extraction during fermentation and maceration. Seasonal variation in anthocyanin concentration can be used as a guide for potential phenolic concentration. Grape water content also varies substantially from vintage to vintage. If high tannin is part of a stylistic choice, the first opportunity to affect tannin concentration is with a juice bleed or saignée. A
saignée is also one of the most effective tools for increasing tannin in wine. Seasons with higher than usual water content or lower than average anthocyanins may be good candidates for a saignée. Two examples are the 2011 vintage on the North Coast of California, a high grape water year, and 2014, a low anthocyanin year. In both of these years tannin potential was low and high tannin wines were difficult to produce without a pre-fermentation juice bleed. If a lower tannin style is desired, low water content would be a warning that tannin extraction may exceed targets and fermentations should be monitored closely. The North Coast 2013 vintage is a good example. Tannin quality becomes increasingly important in high tannin wines. The presence of seed tannin can increase and modify the sensation of astringency present in these wines. Similarly, tannin modification by anthocyanins and other components can soften astringency and add fullness to a wine that would otherwise be harsh. Seed exractablility decreases and tannin modification increases with grape ripening, and these changes can be measured in grapes. Winemakers making high tannin wines can monitor catechin in grape extracts and wait until catechin falls below target levels before harvest. Polymeric anthocyanins, or pigmented tannin, also increase during this time. The ratio of catechin to tannin is an indicator of tannin seediness and the ratio of polymeric anthocyanins to tannin is an indicator of tannin modification. These values can help guide picking decisions and provide information at harvest on the job at hand in the coming fermentation.
GRAPH: Changes in grape phenolics during ripening. Tannin seediness declines and tannin modification increases during the four weeks before harvest.
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Fermentation and Maceration Monitoring tannin during fermentation is increasingly becoming a standard part of red winemaking. The fermentation processes and length of fermentation can be set to hit stylistic goals when information on phenolic composition is available. Sensory evaluation of tannin during fermentation is particularly difficult. Sugar masks the sensation of astringency and hides tannin. The ETS Rapid Phenolic Panel accurately measures tannin concentration, seed extraction and tannin modification from the juice stage through the pressing process. Tannin concentration differences are readily apparent early in fermentation. By the end of a cold soak, tannin differences between lots can often be seen. Sampling points for monitoring tannin concentration are usually set by the timing of decisions. For example, setting the initial fermentation temperature might be determined by analysis at the end of cold soak. An additional data point after a pre-determined Brix drop could be used to refine that decision. Analysis at 15 or 10° Brix could be used to make an early press decision or to decide if a rack and return is needed to increase tannin extraction. Dryness is the usual sampling point for extended maceration decisions. Sampling on both sides of an action can gauge the effectiveness of the process. A sample taken before and after a rack and return can evaluate its effectiveness at increasing tannin. Sampling before and after a tannin addition can often help sort out the opposing effects of adding to the tannin pool against induced precipitations that often occur with tannin adds.
GRAPH A:
GRAPH B:
Evaluation of well designed experiments can be very useful in developing tools for manipulating phenolic style. Side by side comparisons of fermentation variables such as varying temperatures or pump-over frequency can be helpful in deciding how best to deal with fruit from a given vintage. When done early in the season, these trials can help guide decisions for fruit picked later. In general it is a good idea to analyze the first lots of a vintage more heavily to get a feel for the fruit and the general phenolic character of the vintage. Color is often a limitation in reaching style targets in lighter wines. For wines meant for early release, total anthocyanin content becomes critical. Anthocyanins are a major part of the pigment profile of young wines and they have a desirable purple hue. Anthocyanins often are reduced when tannin extraction is maximized. While higher temperatures favor tannin extraction, they accelerate anthocyanin degradation. In these cases, managing wines for maximum anthocyanins may be desirable. Light wines meant for later release, such as a Pinot Noir,
Analysis of ten Napa Cabernet Sauvignon vintages: Chart A shows vintage effects on tannin concentration along with a deliberate attempt to lower tannin in 2010, 2011 and 2012. In chart B, winemaking changes starting in 2009 are apparent in an increase in the polymeric anthocyanin/ tannin ratio.
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require polymeric anthocyanins for long term color stability. In these cases monitoring and optimizing tannin extraction and polymeric anthocyanin formation become more important than preserving free anthocyanins. Many high end wines are deliberately made with high tannin concentrations. As tannin levels increase in wine, the tannin characteristics become more important. While most tannin in wines comes from skins, seed tannin may make up a portion of the total. Seed tannin can be more aggressive than skin tannin. It is more astringent than skin tannin, and the sensation of astringency is more forward in the mouth. Catechin is a good marker of seed extraction in wine, and the ratio of catechin to tannin an indicator of the tannin’s seediness. These two variables can be watched during fermentation and maceration and the winemaking processes adjusted to reduce seed extraction. Seed extraction requires alcohol and heat. There is little seed extraction prior to alcoholic fermentation. Often winemakers will attempt to increase extraction at the start of a ferment to favor skin over seed extraction and lessen extraction pressure at the end of fermentation. Seed removal can be used to reduce potential seed extraction.
binding to tannin can be influenced by winemaking practice. The general level of polymeric anthocyanins in wine is first determined by the tannin level. A low tannin wine will generally have low concentration of polymeric anthocyanins and a high tannin wine will have high concentrations. Oxidation, either through aeration or direct oxygen additions, can also influence formation of polymeric anthocyanins. Winemakers can use the polymeric anthocyanin / tannin ratio to monitor tannin modification. There are considerable differences between wineries in this ratio. Many Cabernet Sauvignons are made with around 1000 mg/L of tannin. Wines with a tannin concentration of 1000 mg/L of tannin can have polymeric anthocyanins that range from 45 to more than 120 mg/L (polymeric anthocyanin / tannin ratios of 0.045 to 0.120 respectively). This difference is largely a stylistic decision influenced by winery practice. Wines at the higher end of this range are more developed, wines at the lower end more fresh. When taken too far, wines at very high polymeric anthocyanin / tannin ratios can seem prematurely aged, while wines at the lower end can seem too raw. Finding the right balance for a specific product requires careful sensory and supporting chemical analyses.
As tannin levels increase in wine, the tannin characteristics become more important.
High tannin wine styles also need some degree of tannin modification to make the tannin more palatable. Anthocyanin
Developing Style Wineries generally have a developed wine style for each product. The style goals are usually based on tasting and evaluating many wines both within the company and in comparative tastings of competitor’s wines. Market considerations are a key to the development process. Adding an analytical component to the
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process can help guide the discussion of what a wine style represents, as well as providing important information needed for influencing style in future vintages. Before analysis can be used to hit style goals there needs to be an analytical target.
EXPANDING our
SERVICE Our St. Helena laboratory is now open year round from 7 AM until 10 PM Monday through Friday. You can drop off samples earlier than ever before and receive your results sooner. Drop samples at our St. Helena location by 7 pm for same day turnaround on core analyses. Our dedicated staff is committed to providing you with fast and accurate results along with their technical expertise and support to enhance your craft.
In addition, in the upcoming months we will be expanding our hours at all of our Satellite locations. Our newly located lab in Newberg, OR will be open Monday through Friday from 7 am to 7 pm beginning Monday July 20th 2015. Our Walla Walla, WA laboratory will launch its 7 am to 7 pm hours on August 3rd 2015. The Healdsburg, CA site will begin extended 7 am to 7 pm hours on August 10th 2015. Drop samples by 6 pm at any Satellite location with 7 am – 7 pm hours for same day turnaround on core analyses.
All ETS lab locations will be open on Labor Day and have weekend and extended hours during harvest. Check our website, etslabs.com, in the upcoming weeks for our harvest hours. ETSLABS.COM |
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COME & SEE US! We’re opening new locations, moving to new spaces and expanding our existing labs. We hope to see you soon! 14 | WINEMAKER’S QUARTERLY
Willamette Valley, OR 214 W. Hancock St. Newberg, OR 97132
Thanks to the overwhelming support we have experienced from the Oregon wine industry, ETS in the Willamette Valley is expanding! We are very thankful to the Davison Family for sharing space with us at their McMinnville location all of these years, and want to thank all of our dedicated clients for your continued support. We will be tripling our laboratory size to expand our customer service providing extended hours, new year round drop boxes and courier options, additional quality staff and an increased number of locally available on-site analyses. Our expanded laboratory is located at 214 W Hancock Street in Newberg. Keep an eye out for updates as we complete construction and introduce our expanded options.
PASO ROBLES LOCATION is currently under construction and will be open in time for Harvest.
Paso Robles, CA 3320 Ramada Drive Paso Robles, CA 93446
Just in time for Harvest, we will be opening a new satellite lab in Paso Robles to offer faster and more convenient services to our clients in the surrounding areas. We will be located in shared building space with our friends from Scott Laboratories, and we are all very excited about our upcoming opening in the Central Coast area. The new lab, located at 3320 Ramada Drive in Paso Robles, will offer core juice and wine analysis on site, using the most advanced technologies available in the wine industry, allowing our clients to receive even faster turnaround for our most requested analyses. Watch for our upcoming opening and service updates.
Walla Walla, WA 3020 Isaacs Ave. Walla Walla, WA 99362
ETS is proud to be an ongoing partner with Walla Walla Community College providing support for the development of the Washington wine industry. Due to the continued industry growth and advancement we are excited to announce not only an upcoming expansion in staffing, but also extended hours and analyses available on site! ETS will offer conductivity testing for cold stability on site providing even faster turnaround. Phenolics testing will also be available on site using the most advanced HPLC equipment and methodologies. We will be announcing these changes as they come on line in the upcoming weeks.
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