Euro Master’s Student Investigates Washington Rieslings
Entering stage right is Washington’s first Vinifera Euro Master.
From the sound of that, you might expect a winemaker wearing tights and a cape to come flying in with advice about what to drink with dinner. But the Vinifera Euro Masters is actually a graduate program coordinated by six institutions in Europe.
“You spend the first year of the two year program studying both viticulture and enology at Montpellier SupAgro in the South of France,” said recent Euro Masters graduate Linn Scott. “Then you spend the first semester of the second year at one of the participating institutions. In my case, I went to Geisenheim.”
Forschungsanstalt Geisenheim, located in the Rheingau wine grape-growing region of Germany, is a focal point of German enological research and education.
“I’m interested in sulfur aromas,” Scott said, “both the positive kind that are characteristic of the tropical fruit aromas of Sauvignon Blanc, and the negative kind that produces rotten egg odors and that typically indicate problems during fermentation.”
While in Geisenheim, Scott was mentored by Dr. Doris Rauhut, one of Europe’s leading experts on sulfur compounds and the aromas of white wines. As it happens, Rauhut is also a colleague of WSU’s director of viticulture and enology, Dr. Thomas Henick-Kling.
“It was the connection to Thomas and Washington State that led me to my research project,” Scott said. Born and raised in Seattle, Scott was intrigued by the idea of doing research in his home state while earning a degree from a prestigious consortium of European universities.
Henick-Kling proposed that Scott work on a Riesling flavor map for Washington state. This survey would describe the range of Riesling flavors produced in Washington. Combining this sensory descriptive analysis with a survey of viticultural and enological practices in the production of Riesling, Henick-Kling suggested, would serve several important purposes, including correlating, to the extent possible, flavor with terroir, as well as addressing a problem found in white wines called atypical aging defect.
“Riesling comprises about 16 percent of Washington’s wine grape production,” Scott said, citing figures from the Washington Association of Wine Grape Growers, “so contributing to our understanding of Riesling farming and winemaking practices seemed like something that would make a contribution.”
Henick-Kling agreed. “Riesling is a signature wine grape variety for Washington. Winemakers here are producing outstanding wines that are getting world-wide attention. Developing a better understanding of the flavors in our Rieslings will help us produce more distinct, high-quality wines.”
Scott interviewed a number of winemakers and vineyard managers to assess the state of the art and science in Riesling production. He also conducted tasting panels of single vineyard Washington Rieslings, both in Washington and in Germany, in order to construct a flavor map.
“What I found was a spectrum of flavors,” Scott said. “There was a cluster around mineral-citrus flavors and another around the riper, peachy and floral flavors. These descriptors were the ones I used because they came up consistently in my interviews with industry professionals.”
Most winemakers, Scott said, associate those differences to the temperatures in the vineyards. The common wisdom is that warm sites produce fruit that result in wines with riper flavors — more peach, more floral flavors. Cooler temperaturess produce wines with mineral and citrus flavors.
Curiously, this association was not borne out by data from WSU’s AgWeatherNet, which records temperatures at 134 locations around the state, including many grape-growing areas. Scott said there were any number of other factors that could produce those flavors independent of the number of degree days (or total heat the grapes are exposed to in the course of a growing season) in the vineyard.
“Among other things, the type of yeast used in the vinification process could confound those results,” he said. Indeed, pioneering work by Henick-Kling shows that the strain of yeast employed for fermentation has a significant impact on a wine’s final flavor profile.
“There was another cluster associated with pear flavor,” Scott continued. “This cluster fell between the ‘mineral-citrus’ and the ‘peach-floral’ clusters. This ester-character could be due to yeast strain or wine age. Then there was a fourth cluster of wines that had all been aged on lees (the residual yeast and other particulates that precipitate out during fermentation and aging). In retrospect, this tells me there were probably some additional flavor descriptors that it would have been useful to employ. What we need is a longer, more controlled study.”
“The first step, and this is the step Linn took,” Henick-Kling said, “is to get a handle on the state of knowledge and the basic flavor groups we find in today’s Rieslings. Unlike other areas of science, where we can go do a survey of the published literature, winemaking is very much an oral or undocumented and sometimes proprietary body of knowledge. So you just have to jump in, start talking to people and, pretty soon, you’ve got way more question than answers.”
“The way it looks now,” Scott said, “is that winemaking techniques have a big impact on the way the wine turns out. That vinification techniques influence wine is really a no-brainer. But exactly how various techniques and practices shape the wine is still largely unknown.”
Scott pointed out that there are several pressing technologies and other factors in pressing could have a big impact on the final product. Recent, award-winning work by WSU’s Jim Harbertson, for instance, sheds some light on this initial stage of the winemaking process. (See sidebar for a link to more information about Harbertson’s work).
And pressing the grapes to extract the juice is only the beginning – or the middle, depending on how you view the process.
“The need for grape growers and winemakers to work hand in hand is clear,” Scott said, echoing the winemaker’s credo that a great bottle of wine begins in the vineyard. “We don’t even really have a clear definition of what we mean by ‘ripeness.’ There are lots of obvious points of control that affect the final product.”
Some of those points of control touch on the mysterious, semi-mystical notion of “terroir.” More of a belief and a marketing term than anything scientifically demonstrable, Scott said it’s a term that gets used a lot – so much, in fact, that it’s difficult to know what is meant by the word. The growing cadres of wine bloggers are notorious for speaking of “tasting terroir” as if it were a scientific fact.
“What we mean by ‘tasting terroir’ is probably not what the French mean by terroir,” Scott said with a note of caution. “But soil and its water-holding capacity, air flow, slope — these are real things, so matching site to variety is important.”
Scott’s study of Riesling flavors dovetails with work being done by WSU graduate student Ian Yau, who is working on a site selection tool for vineyard establishment [[link]].
“On the one hand, you can age a Riesling in new oak, and it’s going to taste totally different from a wine that is aged in a steel tank, it will have a wood flavor we might associate more with Chardonnay,” Scott pointed out. “So the idea of what is ‘typical’ for a particular variety is subjective. On the other, though, the more we can grow a variety so that it produces fruit that makes wine strongly typical of that variety, than the more you may be closing in on the right variety for that terroir.
“That’s something I’d really like to investigate in the future,” said the newly minted Euro Master. “Washington is an exciting place because people in the industry are trying all kinds of things. And that’s great, but it’s OK to specialize, too.”
Scott is weighing his options going forward. There might be a Ph.D. program in his future, as his study of Washington Rieslings has whetted his palate for a further investigation of the correlation between flavor profile and terroir. Then again, a burgeoning industry beckons, so it’s entirely possible Scott will apply his knowledge to an endeavor that will endear him to you as your new favorite winemaker.
by Brian Charles Clark
For more information
Learn more about the Vinifera Euro Master’s program by visiting http://bit.ly/caWOud.
Learn more about viticulture and enology education at Washington State University, including online courses, professional certificate programs, bachelor of science degree programs, and advanced degree programs by visiting http://wine.wsu.edu.
Learn more about efforts at WSU to develop a GIS-based vineyard site selection system at http://bit.ly/a3NywG.
For more information on work being done by Jim Harbertson and his colleagues on the effects on winemaking techniques on flavor profiles, please visit http://bit.ly/9sPXRl.
Thomas Henick-Kling’s research on the effects of yeast on a wine’s final flavor profile is published in the following journals, some of which may be found online.
Porret N.A., Henick-Kling T., Gafner J. “Vertical Distribution of Yeast and Bacteria in Steel Tanks during Wine Fermentation.” Mitt. Klosterneuburg, 57:29-36; 2007.
Bujdoso G., Ittzes A., Henick-Kling, T. “Assessment of fermentation results of Hanseniaspora (Kloeckera) strains isolated in Finger Lakes’ wineries.” Acta Alimentaria. 2002; 31(3): 265-278; 2002.
Egli C.M., Edinger W.D., Mitrakul C.M., Henick-Kling R. “Dynamics of indigenous and inoculated yeast populations and their effect on the sensory character of Riesling and Chardonnay wines.” J. Appl. Microbiol. 85: 779-789; 1998.
Henick-Kling T., Edinger W., Daniel P., Monk P. “Selective effects of sulfur dioxide and yeast starter culture addition on indigenous yeast populations and sensory characteristics of the wine.” J. Appl. Microbiol. 84:865-876; 1998.
Vines and Wines Goes Online
Ask WSU associate professor of horticulture Kathleen Williams about soil snakes, and her eyes light up. “You squish wet soil into a snake shape, and see if it crumbles. It shows texture and water-holding capacity.”
Getting your hands dirty is the first requirement for Williams’ new spring online course, VE 113, Introduction to Vines and Wines, which covers everything from planting grapes to pairing wine with food.
The second requirement is the ability to squish stuff. Take, for example, the process of extracting DNA from strawberries. “You take a couple of strawberries,” Williams said, “squish them up, then add liquid detergent, meat tenderizer and salt. You pour the mush into a glass, and add ice-cold rubbing alcohol.”
This may sound like a particularly gruesome cocktail, but students will see DNA strands rising into the alcohol. “It’s very cool,” she says.
Another experiment teaches the principles of fermentation. “Students squish up fruit, add bread yeast, let it ferment and compare fermentation rates.”
Students also learn how to prune vines, make ricotta cheese (heat milk, add vinegar, strain curds), and detect tannins. Due to underage students, these tannins come in a tea bag, rather than from one of Williams’ favorite reds. (“A really heavy duty Cabernet.”)
The first thing people should know about tannins, Williams said, is that you can’t taste them. You feel them. “Tannins make your mouth feel dry and your teeth feel fuzzy. That’s because tannins precipitate out the proteins in your saliva.”
“If you really want to do a number on yourself, just hold that tannic wine or tea in your mouth for about 10 seconds — if you can stand it — then swallow. You will feel it for several minutes.”
After students recover, they will add fresh lemon juice to the tea to learn how flavor is affected by acid.
“I’m not trying to torture people,” Williams said, “but it’s a good lesson in how those two — acids and tannins — interact.”
Williams is an expert on walnuts, almonds, persimmons, chestnuts, pecans, peaches, pears, apples grapes, cherries, and raspberries — “all the brambles, really” — and her chief area of expertise is in growth regulators and fruit set. She began at WSU Extension in 1988 and has tromped through many a Washington state orchard and vineyard. She gradually shifted to teaching, and became a full-time Pullman faculty member in 2007.
Her interest in horticulture began much earlier in Riverside, Calif. Her mother wanted a good cherry pie — not a store-bought pie, not a pie with canned cherries. She planted a cherry tree in the backyard. It wouldn’t blossom.
“Being an enterprising 10-year-old,” Williams said, “I wrote one of the scientists at the nearby University of California.”
A scientist sent her a letter. “That’s when I discovered that tree fruits have very elaborate mechanisms for dormancy,” she said. “It has to be cold enough so the buds can rest and form flowers. I decided that when I grew up, I was going to study cherries.”
Williams went on to earn a bachelor’s in history from the University of California, Santa Barbara, a master’s in horticulture from U.C. Davis, and a Ph.D. in pomology from Cornell University.
“I wished I’d kept that letter,” she said. “I’d love to thank the person for inspiring me.”
by Richard Miller
“Wines and Vines” is offered through WSU Online, Washington State University’s online degree program: http://bit.ly/bUGZwo.
Talk about Your Cougar Spirit!
We don’t stand up and crow too often but it’s time to brag. Here’s proof once again that an enviable climate, lots of smart, hard-working talent, and great science-based educational programs pay off big time.
Six Cougar-connected wineries made Wine & Spirits magazine’s 100 Top Wineries list for 2010.
All six wines have been featured in the WSU Alumni Association’s Wine by Cougars wine club.
The six participating Wine-By-Cougar wineries named among Wine & Spirits magazine’s most recent top 100 wineries of the year are:
- Amavi Cellars, Shane McKibben, vineyard manager, Walla Walla
- Chateau Ste. Michelle, Ted Baseler, president and CEO, Woodinville
- Fidelitas Wines, Loren Hoppes, owner, Benton City
- L’Ecole No. 41, Jean Ferguson, founder, Walla Walla
- Leonetti Cellars, Chris Figgins, CEO and director of winemaking, Walla Walla
- Pepper Bridge Winery, Shane McKibben, vineyard manager, Walla Walla
The list praised 3 other wineries from Washington and 37, total, from the United States.
For more information and to learn more about WSU alumni wineries, visit http://bit.ly/bIB5hH.