What the Nose Knows - Avery Gilbert [3]
We moved to Davis because my father joined the faculty of the philosophy department at the university there. Davis was originally the agricultural field station for the main university campus at Berkeley. Set in the hot, flat, and fertile Sacramento Valley, but near the cooler hills of Napa and Sonoma, UC Davis came into its own in the 1960s, when it added a law school and a medical school. At the same time, researchers in the Department of Viticulture and Enology got the ball rolling for what became the California wine-making revolution. They measured microclimates and soil composition, developed new grape varieties, and invented cold fermentation and other wine production techniques. Davis graduates who took courses in wine-tasting and wine-making are now among the world’s leading vintners. As part of this effort, UCD researchers took up the sensory analysis of wine. Their challenge was to apply objective methods to one of the more rarefied arenas of subjective opinion: wine-tasting.
One of this group was Professor Ann Noble, a chemist and sensory specialist. Among her interests was identifying volatile chemical compounds in wine. These substances create the characteristic aroma of grape varieties such as Cabernet Sauvignon or Riesling, and also the off-odors found in poorly made wines. Noble hoped to link aroma chemistry to broader grape-growing and wine-making factors.
Noble’s approach to aroma was practical and effective. Not for her the pretensions of the wine snob, epitomized by Paul Giamatti’s character in the movie Sideways, who sticks his nose in a wineglass and says, “I’m getting strawberries, some citrus…passionfruit, just the faintest soupçon of asparagus, and, like, a nutty Edam cheese.” To better understand California Cabernets, Noble and her colleague Hildegard Heymann selected wines from seven regions around the state (Napa, Sonoma, Alexander Valley, Santa Ynez, etc.). The wines were rated by enology students who came up with their own simple descriptive terms: berry, bell pepper, eucalyptus, and so on. Reference samples were created by doctoring a neutral “base” wine. To represent berry, for example, one-half teaspoon of raspberry jam and one half of a frozen blackberry were added to a half-cup of wine; after soaking for ten minutes, the blackberry was removed. For the soy/prune standard, the basic wine was spiked with a quarter-cup of canned prune juice and seventeen drops of Kikkoman soy sauce.
Armed only with their noses and a nine-point rating scale, the students sniffed and sipped their way to an enormous pile of data. (It filled a metaphorical filing cabinet thirteen descriptors wide, twenty-one Cabernets tall, and thirteen judges deep.) With a computer program, Noble and Heymann extracted a small number of sensory dimensions and placed each wine at a precise location on them. They could now visualize the smell and taste relationships between the samples. Their conclusions: “Younger vines and/or vines from cooler areas tend to produce more intensely vegetative wines. Conversely, wines from older vines and/or warmer areas tend to have higher ratings for berry aroma, fruit flavor by mouth, and vanilla aroma.” By quantifying wine aromas with a system of practical description, they discovered the vineyard conditions that produce them. Alexander Graham Bell would have been pleased.
WHAT EARNED