Last Month’s SF Bay Area Heat Wave Mows Down Winemakers

The recent egg-frying heat wave that hit us a few weeks ago (and sold out every fan in the entire SF Bay Area) is making its mark on our area’s winemakers. Temperatures in Napa and Sonoma shot up to 117 degrees, and the impact of the heat will affect between 5 percent and 35 percent of the harvest. In the record-setting heat grapes just shriveled on the vine as their juices evaporated. Because they weren’t ripe, this leads to higher alcohol content and an unsuitable flavoring for making wine.

A Bloomberg story on the vintners challenge said that the varietal grape types hit the hardest include cabernet and petit verdot. The white and sparkling varietals went through the heat wave fairly intact.

According to Bloomberg: “Some winemakers, like Newton Vineyard winemaker Rob Mann, stretched long shade cloths against one side of each vine row to ward off the sun’s rays in the hottest stretches of the afternoon. Cathy Corison, like many vintners, picked at night last week, when it was cooler. She’d sleep for three hours before heading out at 12:30 am to the vineyards with a headlamp, then work through the night with a team of pickers.”

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