Bay Area heat surges spark worry among Napa wine growers

ST. HELENA, Calif. (KGO) -- There's a new wrinkle among the grapes this harvest season. Many more wrinkles, actually, and on the grapes, themselves.

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Blame four days of late-season, pre-harvest, 116-degree heat in the Napa Valley. At Crocker & Starr Winery in Saint Helena, a good portion of what should be ripe, plump, prime Cabernet grapes look more like raisins.

When asked how much she's lost this year winemaker and co-owner, Pam Starr, said, "About 25 percent. I've never seen anything like this in 34-years."

That's no small loss for a boutique winery producing roughly 3,500 cases per year.

The dried grapes mean more time and effort, both in the vineyard and in the barrels.

If too many raisins find their way into the wine, they could reduce its longevity.

"Well we're going to have to be winemakers," said associate winemaker Evyn Cameron. "Some years you let the vintage do the work for you."

Is it climate change? Just strange weather? There is no way to know, as of now. But, when they tell the story of this vintage from 2017, it will certainly be a different one.

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