The latest in a string of heat waves this summer has complicated a wine grape harvest that vintners had considered a post-drought return to normal.
Triple-digit afternoons in California’s prime wine-producing regions early this month left vintners scrambling to take protective measures to keep grapes from shriveling on the vines before crews could pick them.
In the Napa Valley, where temperatures reached as high as 107 degrees on Sept. 2, growers say fruit quality remains high because of winter rainfall and vineyard practices they employed during the growing season.
Heavy winter rains replenished reservoirs and brought soil moisture levels back to full capacity, said Heidi Soldinger, the Napa Valley Grapegrowers’ marketing and communications manager.
“Grapevines draw from these stores of moisture throughout the warmest summer months,” Soldinger said in an email. “In this way, stable soil moisture levels act as a natural heat buffer. Also, to date, air humidity levels remain high, even on the hottest days. The wet air, as with soil moisture, acts as a cooling element in the heat.”