FALL 2014
VOL. 1 / ISSUE 1
WINEMAKER’S Q UA RT E R LY PRESENTED BY ETS LABS
- F E AT U R E High and Dry: Drought in the West -QUESTIONS? Answering Your Harvest Questions -PROFILE Q&A with Marjorie Burns
TABLE OF CONTENTS VOL. 1 ISSUE 1
FALL 2014
2
Welcome
3
Sluggish Fermentation
4
Harvest Questions
5
Drought in the Valley
7
Profile: Marjorie Burns
T
he smells of harvest are wafting through the valley, berries are slowly turning into wine, and it seems that everyone is working around the clock to create this year’s masterpieces. The winemaking process is an art, and ETS is supporting winemakers with powerful tools and scientific guidance every step of the way. Harvest is an exciting and trying time, but at the end – when the new vintage is released to the world – we all remember why we continue doing what we do. As part of our efforts to support the art of winemaking, we’ve collected some useful information and observations to send to our clients. We hope you’ll enjoy reading them - in this issue we’ll look into stuck fermentation (pg. 3), focus on the drought that is affecting the whole west coast (pg. 5), and share answers to some of the questions we are asked most often (pg. 4).
Here’s to harvest 2014
Our thoughts are with the wineries and families who were affected by the earthquake in California - we’ll be here to support and assist you as you pick up and push forward to craft your newest vintage. So here’s to harvest 2014! We hope it is the best one yet for you and your team.
Questions or feedback? Send us a note: Editor@etslabs.com
-From Everyone at ETS
Feeling Sluggish?
S
Fermentation, the basis of all winemaking, is an amazing process: yeast strains have learned to out-compete many of the other microbes in their environment by producing high levels of ethanol. It’s a stressful and difficult adaptation, and depends on healthy yeast. low fermentation rates, or incomplete sugar utilization, are usually symptoms of stress on the yeast, either from nutrient limitations or from physical and environmental stress factors, such as temperature, ethanol toxicity, inhibitors, or competing microbes.
While the wine industry gives plenty of attention to yeast nutrition from nitrogen and sugar, we often overlook another macronutrient that can be just as important: phosphate. Low levels of phosphate can have a limiting effect on yeast, impacting cell growth, reducing biomass yield, and directly impacting the fermentation rate. Historically, using DAP as the main nitrogen supplement probably masked phosphate deficiencies from poor soils. Now that winemakers are increasingly using other sources of nitrogen supplementation, fermentation problems linked to phosphate deficiency could become more common, especially in acidic soils with high iron and aluminum content. Temperature is a common stress factor that can have a deadly effect on yeast. Pinpointing the maximum temperature your yeast can handle is tricky: each strain has a different temperature tolerance, and the more it’s stressed early in fermentation, the lower the peak temperature that your yeast can survive. Limited supplies of nitrogen can also lower yeast’s heat tolerance by limiting its ability to protect itself with heat shock proteins.
Prevention is critical, because once it’s stuck, it is often difficult to push a fermentation to completion. You are the only one who can who can recognize when a fermentation is abnormal or problematic, because the definition of “normal” is based on your individual fermentation profiles. The best way to prevent stuck and sluggish fermentations? Pay attention to the basics: Check yeast health at inoculation, and know the nitrogen status of the juice and wine, as well as the initial sugar (potential alcohol.) It doesn’t stop there, though – make sure your fermentation stays on track by monitoring temperature, fermentation rates, and competing microbes. Once a fermentation is stuck, analysis becomes a forensic tool instead of a predictive tool. Understanding the causes of problems and paying careful attention to the basics are the first line of defense to help you get the most out of your harvest.
Long Lag Phase Sluggish
Normal to Sluggish
While it’s easy to spot a stuck fermentation, sluggish fermentations can be much harder to pinpoint. A “normal” fermentation looks different depending on how you make wine: the temperature, yeast used, inoculation rate, and other decisions give each winery a different “normal.” Sluggish fermentations are those with a lower than expected rate of fermentation, based on the historical “normal” fermentation profile.
While there’s no magic temperature to prevent problematic fermentations, there’s evidence that keeping things cooler might help alleviate problems caused by other stress factors. In one study looking at known causes of stuck fermentations, those run at cooler temperatures all finished fermentation.
Normal
Common Problem Fermentations:
Winemakers sometimes disagree about optimal fermentation temperatures, with typical fermentations ranging anywhere from 45-65º for white wines and 70-85º for reds. Some will run red wine fermentations even hotter in an attempt to maximize phenolic extraction.
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Questions and Answers We’ve picked out a few questions that seem to come up the most during harvest. Every issue, we will share new questions to help with current issues or trends that we’ve seen.
Should I test for glucose + fructose or ºBrix for alcohol predictions?
Measuring ºBrix gives a quick estimate of sugar content, but it’s not an accurate representation of the fermentable sugars. Checking Glucose and Fructose gives a much more reliable measurement of fermentable sugar. (Keep in mind that G+F numbers often appear higher than the corresponding ºBrix, because ºBrix values vary with the density of the juice, while G+F aren’t impacted by juice density.) Potential alcohol can be calculated based on the amount of Glucose+Fructose in juice. It’s important to remember that the actual conversion rates vary depending on yeast and fermentation conditions, so your actual alcohol may be lower or higher than the estimate. Predicting potential alcohol in red juice can also be tricky since the Glucose+Fructose results may not reflect the “green”, dehydrated, or over-ripe berries in the tank. Measuring Glucose+Fructose and alcohol simultaneously, after an initial drop of 10º Brix, can provide a better estimate of potential alcohol in red wine.
Can’t you just look under the microscope to tell me what is in my wine?
Microscope examination is a rapid screening tool for the detection of yeast and bacteria. While the microscope may be a quick and costeffective option, it has several shortcomings. A microscope is a powerful tool and is useful for observing large populations of microbes. However a main drawback is the lack of sensitivity at low population levels. Microscopic detection of yeast or bacteria requires a relatively large number of organisms (>10,000 cells/mL) in order to be detected. In addition, positive identification of specific genus and species is difficult with microscopy due to shape and size variability among a unique species. It is also difficult to determine if microbes are dead or alive with standard microscopy methods. While microscopic examinations are useful for qualitative screening, other analytical tools ( such as ScorpionsTM) are more appropriate for quantitative genus and species identification. In addition, ScorpionsTM can detect low levels of the live organisms present in your wine.
Should I be worried about smoke taint this harvest?
The west coast experienced many wildfires this season near winegrowing regions. When vineyards are exposed to smoke, smoke components are absorbed by vines and accumulate in grapes, especially in the skins. The finished wines can display a smoke taint character that is often long-lasting and lingers on the palate. Grapes can be screened for smoke taint by measuring trace levels of free guaiacol and 4-methylguaiacol in whole berries. Knowing the levels of these indicator compounds in grapes lets winemakers forecast the risk of smoke taint in their wines. Smoke compounds can accumulate in berries all the way to harvest, so we recommend screening as close to picking as possible. Smoke taint treatments are limited – there are a few options available when making white wines, but attempts to treat the problem during red winemaking are often disappointing. Reverse osmosis or ultrafiltration techniques seem to have the most success in finished wines, but have stirred some controversy.
High Dry: & A Year With Little Water
Lack of water in winegrowing regions this year is a much larger issue than water restrictions. Lack of water in the vineyards can lead to multiple problems for winemakers to overcome during Harvest.
California is experiencing one of the worst droughts in history. It’s expected to cost the state $2.2 billion and 17,000 jobs, according to a report published in July by the UC Davis Center for Watershed Science. The drought has some residents of the state questioning wineries’ water consumption and has even forced some growers to abandon vines in the most affected areas. It also has many wineries and growers wondering what the effect will be on their wines this year. Water usage and water content have a corollary relationship, one which most winemakers don’t consider much until they have a challenging year like 2014. Grapes are more than 80% water, yet many winemakers ignore water content as an analytical metric. Water content can have a direct impact on other analytics such as tannin, sugar, and acidity levels. It may seem obvious, but water affects dilution and concentration of all these components. How water is used in the vineyard can have as much of, or even greater impact on the final wines as how much water is used. The timing of water use also has great potential to impact wines. Final grape water content is influenced from the very beginning of berry growth. Lack of water early in the growing season can limit cell growth, which leads to smaller berries and lower yields. In addition, this produces >> Continue ETSLABS.COM
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>> Continued from previous page
In the winery, it’s a common practice to bleed tanks (saingee) to increase the solid-to-juice ratio before fermentation or during maceration. Of course, this concentrates tannins, which greatly affects the style of wine. By measuring water content, a winemaker can determine to what extent, if any, this process needs to be done. Without having an understanding of the existing ratio, the winemaker may end up with lower or higher tannin levels than desired. Here’s another reason: measuring water percentage can lead to a better predictor of press yields. While California may be thirsty, in 2013 the Willamette Valley in Oregon had a relatively wet season. This led to higher water content and subsequent press yields of around 20% higher than expected. Understanding variations in water content gives winemakers a powerful tool to make more accurate predictions of production yields, allowing them to think in gallons per acre instead of tons per acre. Measuring water usage in the vineyards and grape water content through harvest can help winemakers predict tannin levels and final yields today, while benefiting tomorrow by utilizing this analytical data to develop a greater understanding of their long-term water needs.
California
Percentage %
93.86%
100%
23.60%
2011
2012
2013
2014
Oregon
55.62%
Percentage %
Limiting water later in the season may cause dehydration and shrivel. Loss of water late in the season can also lead to a loss of yields which will push sugar levels up. For example, a 15-20% water loss may push ripeness from 23 degrees to 26 degrees. In reality, sugar levels near harvest will fluctuate more depending on water content than on “ripeness” levels. Excessive water may cause dilution and/or bursting. So why is measuring water content important? Water percentage can be used in the vineyard to determine irrigation needs. For example, by adjusting irrigation late in the season, the grower can increase hang time and allow for more physiological development. Water can also have a direct impact on yield changes. A small change in water percentage can contribute to a large change in yield.
Percentage of Each State in Severe Drought
33.72%
1.07% 2011
2012
2013
2014
Washington
Percentage %
a higher skin-to-juice ratio, leading to higher phenolic and tannin levels. More water early in the season may have the converse effect of increasing berry cell size, leading to larger yields, lower skin-to-juice ratios, and more dilution.
18.27% 2011
2012
2013
2014
*Data collected from The National Drought Mitigation Center
HARVEST with
ETS LABS FALL 2014
For your convenience, we have extended our hours during harvest. We also offer weekend service and free sample pickup in many areas to help you get the results you need, when you need them. Visit our website for full details and harvest hours: etslabs.com/harvest
6 | WINEMAKER’S QUARTERLY
Another Year,
Another Harvest
ETS will be celebrating its 37th harvest this year. Marjorie Burns, founder and co-owner, relives the old and discusses the new.
Q: How did you get started in the wine business? A: I was working as a medical technologist, and I used my lab skills to put myself through the graduate Viticulture and Enology program at UC Davis. I had the privilege of working with Dr. Cornelius Ough, both in his research laboratory and as my major professor. My thesis work focused on the effect of suspended solids on fermentation rates, and their potential impact on stuck and sluggish fermentations. Back then, UC Davis didn’t have a teaching winery facility, so all of our winemaking was done in 5 gallon demi-johns.
Q: What did you do before ETS? A: After graduate school, I worked in Napa Valley wineries learning how to
make wine on a commercial scale. My time in the cellar taught me real-life winemaking skills that couldn’t be learned elsewhere.
Photo by Bill Tucker
Q: How does that compare to harvest season today at ETS? A: The process is completely different now; as more and more yeast and
bacterial strains became available commercially, liquid cultures went the way of the dinosaurs. The harvest ritual of creating the liquid cultures is a relic of the past. Today winemakers have a wide selection of commercial yeast and bacteria strains that can Q: Why did you decide to start a wine laboratory? be directly added to musts and wine. A: I actually went into the wine business to get out of the laboratory As the years progressed, so has the business. There were only a small handful of wineries in the Napa and knowledge of grape composition and Sonoma valleys then, and winery jobs were a scarce commodity. I decided its effect on wine quality. Picking to take matters into my own hands and started a small consulting service, decisions no longer rely on just TA, ETS, offering help to my entrepreneurial students. Since I needed accurate data to help my former students make good winemaking decisions, I set up a pH and brix. Grape maturity and small lab in the basement of my house. The response for analytical services composition influence flavor and was overwhelming, and ETS made the natural evolution from consulting to quality, so winemakers use many more analytical tools, including juice panel, moisture, and phenolic analyses to determine optimum picking time. analytical services. I was back in the laboratory business after all! I also taught the first Winemaking and Wine Appreciation classes at Napa College before there was a formal Enology program. Since the college didn’t have any vineyards or winemaking facilities, my classes learned to make wine in the basement of my house using a drum of frozen grapes. Many of my students were adults who were starting small wineries.
Q: What was harvest like when ETS first opened? A: When ETS first started, there weren’t any commercially prepared
bacteria cultures available, and only a handful of dried yeast strains were available from Red Star. Every harvest we would spend hours preparing batches of culture juice media that we autoclaved in one-liter bottles, then inoculated with yeast or bacteria strains and incubated to produce starter cultures for the wineries. Winemakers would use the liquid starter cultures to build up enough volume of active organisms to inoculate their juices for primary or malolactic fermentations. Building the correct amount of successful starter culture in the winery for transfer was a time-critical task that each winemaker had to plan as part of their harvest program, since commercial cultures were not readily available.
Harvest always brings a renewed vibrancy and enthusiasm.
Q: Is there something about harvest that you look forward to each year? A: Each harvest is exciting because it always brings new energy and vitality
to the entire wine growing region, along with the harvest noises and aromas that accompany it. Each harvest is unique, bringing its own challenges and personality into the current vintage, and creating new opportunities to learn. Harvest always brings a renewed vibrancy and enthusiasm to the winemaking community and bonds the ETS staff together to meet the challenges of time-critical harvest demands, high workload, and extended hours to help our clients. I look forward to the teamwork and collaboration that happens every harvest as neighbor helps neighbor, and we all work together to get the job done.
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