(Cen.Acs) - After the smoke had cleared from the October wildfires that ravaged more than 970 km2 in Northern California, Anita Oberholster started getting phone calls. Winemakers had harvested most of the grapes in the Golden State by the time the fires began—90% of the tonnage in Napa Valley had been picked, for instance—but some were still on the vines. And winemakers had questions.

Many were familiar with “smoke taint,” the decidedly unpleasant, ashy flavor wines can take on after grapevines have been exposed to smoke from wildfires. But the approximately 1,200 wineries in the area of California where the October fires burned had never experienced blazes quite as intense as these, particularly during harvest season, when grapes are most sensitive. The winemakers calling Oberholster wanted advice on how they could determine whether their grapes had been tainted.