learning to Taste Wine : Participants in a UC Davis extension course devote their weekend to the serious study of wine.

Could anything be more lax, loose and low-pressured than a weekend spent learning to taste wine? The answer is yes, almost anything, if the weekend in question is devoted to a UC Davis course titled “Introduction to the Sensory Evaluation of Wine.”

At Davis, “Sensory Evaluation” is not a euphemism for drinking. The university is renowned for its department of viticulture and enology and promotes the serious study of wine through the senses of sight, smell, feel and taste. It is even possible to go through the two-day course without drinking because the approved procedure is to spit the wine into large plastic buckets.

Offered only twice a year by the university extension, the course requires eight hours a day of concentration and heavy note taking. If faces become flushed, it is from the struggle to detect and describe elusive aromas given off by wine and to measure such attributes as acidity, sugar, bitterness, astringency and viscosity. If heads buzz, it is with technical terms like mercaptans, phenols, diacetyl, brettanomyces and zygosaccharomyces that are tossed off with ease by enology department professors who appear as guest speakers.

Reading material includes papers on “Phenolic Extraction Curves for White Wine Aged in French and American Oak Barrels,” “Comparison of Citric, di-Malic and Fumaric Acids as Wine Acidulants” and “The Contribution of Glycerol to Perceived Viscosity and Sweetness in White Wine.”

This is no snap course, in other words. But it does have its moments of humor, thanks to the low-key manner of the instructor, John Buechsenstein, who is wine maker at McDowell Valley Vineyards in Mendocino County.

Buechsenstein initiated the course in 1979 while a graduate student at Davis and now schedules it for the months when he is not busy making wine. Participants in the mid-January session included home wine makers, grape growers, a bulk wine broker, plumber, winery publicist, manager of a winery restaurant, a part-time winery worker, members of winery-owning families (including a man from Oporto, Portugal, who had been working in Napa) and just plain wine appreciators. Most were from northern California, but a few came from the southern part of the state, and one journeyed from Arizona.

Larry D. Shaw of Mesa, Ariz., a pathologist who plans to open a brew pub, was taking the course for the second time. Recalling his first go-round, Shaw said, “I felt humbled by the end of the first day.” This year, Shaw said he could see that he had “really learned something” the previous time and felt more comfortable describing wines.

Translating aromas and flavors into words can be difficult, and the adjectives applied to wine often seem far-fetched. In the class, descriptions ranged from the pleasant “fresh” and “fruity” to the unflattering “skunky,” “rotten eggs” and “dirty feet” to such heights of creativity as “old rain gutters,” “mouse’s urine” and “wet dog in a phone booth.” The last two terms were contributed by Ralph Kunkee Ph.D., a microbiologist and enology professor who lectured on “Wine Microbes: Success or Spoilage?”

In his address on “Wine Aging: Barrel and Bottle,” Vernon L. Singleton Ph.D. linked rain gutters to the unpleasant flavor imparted by redwood storage vessels. A specialist in storage and aging reactions, Singleton is a veteran of almost 30 years at Davis. He is co-author with Maynard Amerine, now professor emeritus, of the book, “Wine, an Introduction” (University of California Press).

The remaining guest speaker was Roger Boulton Ph.D., associate professor of enology and chemical engineering. In his discussion of “Sensory Effects of Wine Processing,” Boulton took up the issue of style versus character of the grapes as the dominant influence in shaping a wine.

Participants paid $200 to enroll in the class, which was held in the Faculty Club on campus. After coffee and sweet rolls or muffins each morning, they buckled down to work at 9 a.m. The subject matter was so concentrated that breaks lasted only a few moments, and the sessions ended later than scheduled.

The fact that wine is linked to the good life was not lost in the wealth of technical information. Lunch each day was part of the program and included two wines selected by Buechsenstein. The first day’s menu of lasagna, California tossed green salad, cheese bread and lime sherbet was accompanied by 1986 Estancia Alexander Valley Cabernet Sauvignon and 1984 Fitch Mountain Cellars Zinfandel. At the end of the day, Spanish sherries and a French aperitif wine were set out for a social hour.

On Sunday, there were white wines--R.H. Phillips Vineyards 1985 Hillside Chardonnay and Trefethen Vineyards Eshcol White Wine--to go with Cornish game hens and rice stuffing, spinach salad, poppy seed rolls and chocolate layer cake.

Anyone who expected the weekend to consist of non-stop tasting would have been disappointed. Buechsenstein did pour a mystery wine right off to introduce the evaluation process. But serious tasting was reserved for Sunday afternoon so students could practice what they had learned.

The first lesson dealt with the visual evaluation of wine--its color and clarity. As students filed into the classroom, they were greeted by rows of glasses holding wines ranging in color from the brown-tinged red associated with an oxidized old wine to the cloudy yellow of a barrel sample. One glass held a white wine that contained tartrate crystals. Another held pieces of cork on which crystals had formed.

Practice in olfactory evaluation came next. “Most of what constitutes the flavor of a wine is caused by the fact that we smell it,” Buechsenstein said. For this session, he had doctored wines to give off the scents of raspberries, grapefruit, honey, vanilla, green olives, canned asparagus, sweet red pepper and other substances with aromas similar to those that appear in wine.

For taste tests, wines were treated to show sweetness and acidity, volatile acids, varying degrees of alcohol and the effects of the addition of fining agents such as egg white. To single out oak flavor, Buechsenstein paired a solution of French oak extract with a Cabernet Sauvignon that had been aged three years in the same type of oak.

In the comparative tastings, the wines were rated using the 20-point Davis score card, a modification of a scoring system that had been introduced years earlier by Amerine.

In the 20-point system, points are either allotted or deducted in seven categories: appearance, color, aroma and bouquet, acidity, sugar, flavor by mouth and general quality. Aroma and bouquet is the dominant category, receiving a maximum of six points. (Aroma originates with the grapes; bouquet is developed during processing and aging.) Flavor by mouth (acidity, sweetness, body, astringency) ranks next with five points. General quality rates a maximum of three points. Color and acidity can earn two points each, and appearance (clarity, brilliance, bubbles in a sparkling wine) and sugar come last with one point each.

To demonstrate the scoring system, Buechsenstein led a tasting of the mystery wine (later identified as 1986 Husch Vineyards Gerwurztraminer), a Chardonnay and Cabernet Sauvignon. Then students practiced their skills in blind tastings of six 1985 California Sauvignon Blancs and six 1984 Zinfandels. “These are two wines you can always count on to show a lot of variety and difference in style,” Buechsenstein said.

At the beginning of the course, Buechsenstein warned that the subject matter would be detailed and technical. The goal, he said, was to excise the “purely hedonic responses to wine” that are typical of social tastings.

By the end of the weekend, participants had gained not only tasting skills, but an appreciation of the complex decisions faced by wine makers and a reassurance about the wines they would drink in the future. “In California wines as a whole, you’ll find a lot fewer flaws than you think,” Buechsenstein said.