It hits you in the entrance of Everson Hall: an overwhelming caramel ember wafting from Room 126. There you’ll find students roasting, grinding, and brewing away as part of Design of Coffee, a chemical engineering course disguised as a café that’s become U.C. Davis’s most popular class. Started in 2013 by professors William Ristenpart and Tonya Kuhl, it breaks down our daily cup of Joe into the finest of grounds: the complex combinations of 1,000 volatile compounds that make coffee taste the way it does.
The Design of Coffee is the beginning of something grander—U.C. Davis’s new Coffee Center, the first institute in the world to scientifically study the production of coffee, due to open later this year. It’s U.C. Davis’s attempt to do for coffee what its enology program, which powers nearby Napa Valley, has done for wine: build the scientific expertise to support the nation’s habit.
In the meantime, the Design of Coffee class has minted more than 1,500 brainy baristas just in the past year. First, they have to participate in an unorthodox final exam: a competition to make the best cup of coffee. “There’s no one molecule that’s coffee flavor,” says Ristenpart. “If there was, it’d be really easy. It’s really a witch’s brew.” Brewing is the process of dissolving grounds in water, of course, but also of extracting flavorful molecules from those grounds. The students’ task is to use just the right amount of water—even a strong cup is 98 percent H₂0—and to extract just the right amount of molecules. When hot water washes over grounds, the first molecules to be extracted are acidic; brew for too short a time, and the coffee will be pale and tart. After a while, though, the bitter molecules come out. The goal is to extract about 20 percent of the molecules, creating a rich, smooth brew.
It’s coffee as tasty optimization problem, something any chemical engineer can appreciate. Juniors Perry Costa, Christy Burnard, and Ashokan Pillai won the competition last semester with a fine-ground dark roast, water that was just hot enough and brewed about 40 seconds in an AeroPress, a brewer invented by, of course, an engineer. The judges? Two executives from Peet’s, the national coffee chain, which recently donated $250,000 to establish an experimental roastery at the Coffee Center.
“For people who have never tasted freshly roasted coffee—they’re used to something that’s been sitting around for a long time—it can be an eye-opening experience,” says Ristenpart. “Especially if you get something that’s been roasted perfectly, so you get the more exotic floral, or citrus, or berry flavors. Eye-opening.”