UC Davis Professor Challenges the Science Behind Terroir

UC Davis professor David Mills set out to challenge the mystery of terroir, the elusive idea that grapes’ environment contributes to the distinct aroma and flavor of wine.. 

Traditionally, the explanation of terroir has been focused on “weather patterns, geography and cultivation techniques, and soil composition,” according to The Sacramento Bee. However, this concept was never scientifically proven. Mills, on the other hand, is closely observing unique colonies of yeast, fungus and bacteria as a contributing factor in determining wines’ regional differences.

Mills and Nicholas Bokulich, a UCD graduate student, “analyzed 273 samples of zinfandel, cabernet and chardonnay musts (the skin, seeds and stems from mashed grapes) from Napa, the Central Coast and Sonoma,” and have found patterns in the composition of yeast and bacteria, depending on where the grapes were grown. 

Although his study is not yet complete, it has already met with a lot of criticism from the wine community due to oversimplified coverage from media outlets. Mills is currently working to correlate the chemical composition of wines with the microorganisms in the wine must. Then, he will study how microbes affect the flavor profile of finished products. 

“At this point, asking me whether I believe in terroir is like asking me if I believe in God — it’s very difficult to prove or disprove,” says Mills. “But people believe in it fervently.” [The Sacramento Bee] [Photo: Flickr/Sarah Ackerman]