A year ago this week, a series of fires broke out in Napa, Sonoma, and Mendocino counties, one of California’s best-known wine growing regions. While 90 percent of the grapes in Napa County had been harvested, a few vineyards still had grapes on the vine, including at the UC Davis experimental station in Oakville. Wildfire smoke can ruin wine. Anita Oberholster, a viticulture and enology extension specialist at UC Davis has been researching so-called smoke taint, in hopes of finding ways to mitigate the effects.