For five of the past six years, heavy smoke from nearby wildfires has engulfed vineyards full of grapes that Ashley Egelhoff depends on to produce her wine. While some wine drinkers may enjoy a little smokiness in their Zinfandel, too much can render a bottle kaput. When grapes are exposed to wildfire smoke, they soak it up like a sponge. That creates a condition known as smoke taint, which can make a glass of wine taste like it’s been burnt — or worse, served directly from an ashtray, according to vintners and researchers. Egelhoff, the winemaker at Honig Vineyard & Winery, has been forced to...