California hit by record temperatures

Published: 23 July, 2008

by Larry Walker
Grape growers throughout California are keeping an uneasy eye on the weather while getting ready for the 2006 harvest.

After a record-breaking heatwave seared all of the state in July, there were fears that the 2006 harvest might be remembered as the first global warming wine grape harvest.

Record-breaking heat hit all of the state's winegrowing regions, including the Napa Valley, where temperatures of up to 115F were recorded in the vineyards, with even the usually cooler Carneros vineyards, within view of San Francisco Bay, topping 100F, according to viticultural consultant Kelly Maher.

Because the high temperatures hit before veraison, growers and winemakers do not believe that the flavour profile of the grapes will be affected. If it had come in September, it would have cooked the flavours,' Maher said.

Andy Beckstoffer, who farms thousands of acres in Napa, said that recent innovations in canopy management, introduced in anticipation of higher temperatures, helped minimise heat damage in July. New techniques include leaving more leaf protection for grapes, especially on rows with exposure to more intense afternoon sunlight. We also had advance warning that the heat was coming and we poured on the irrigation,' he said.

Still, the full effect of the July heatwave, when temperatures almost everywhere in California crested several degrees above 100F and stayed there for several days, won't be known until closer to harvest, about the first week in September. The only obvious impact at this point appears to be smaller berries, and on the positive

side, this could lead to more intense flavours.

Karen Ross, executive director of the California Association of Winegrape Growers (CAWG), said outside of Napa and the North Coast, the damage could be greater because grape maturity was farther along.

All I can say at this point is that we don't know for sure what the heat did to potential flavour and to the ripening pattern of the grapes. The vines shut down when temperatures get that high and the ripening process stops. We just have to wait and see.'

Most growers are optimistic, saying that if the rest of the growing season is normal, there is no cause for alarm. But if another heatwave should hit before harvest? It could be a disaster,' said Maher.

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