DAVIS (CBS13) — A year after wildfires devastated California’s wine country, wineries are still unsure of the impact of smoke on the grapes.

Several wineries have turned to UC Davis in hopes of avoiding the pitfalls of smoke taint.

Anita Oberholster isn’t doing any ordinary wine tasting in her UC Davis cellar. She’s testing wine grapes, specifically for a cabernet sauvignon, for smoke taint.

“Growers started calling me and said they’re not going to harvest their grapes,” she said.

Some aren’t making wine this year while others are fermenting their grapes and waiting on Oberholster to give them a green light to bottle and sell. She began studying wine grapes in Napa and Sonoma counties after the devastating wildfires in 2017. She’s expanding her research to Lake and Mendocino counties.

“What happens during a fire is a lot of these compounds are released in the air and then absorbed in the grape berry, so now you get an excess amount of it,” she said.

There’s a specific aftertaste she’s looking for.

“When you get that characteristic retronasal, really cold ashtray, cold old campfire taste in the back of your throat,” she said, describing smoke taint.

The cost of smoke taint can be high. Copper Cane, which is based in the Napa Valley, canceled contracts to buy 2,000 tons of grapes from Oregon after fears of smoke taint. Those grapes were valued at $4 million.

Red wine grapes are more vulnerable to smoke taint than whites. Even then, a lot of wines have naturally smoky notes, making it hard to determine the difference between taste and taint.

“It really depends on how close you were to the fire, the wind direction,” she said. “There are so many factors.”

Even if grapes are tainted, she says options such as reverse osmosis are still available instead of chucking the harvest.