FRESNO -- As you contemplate that Thanksgiving wine you relished on Thursday, ponder for a moment a world too hot to grow fine grapes.
Sanliang Gu does every day.
For a dozen years his obsession has been to manipulate the growing cycle of grapes around Fresno, California's hottest and therefore earliest-ripening wine region. This past week he succeeded: The 2011 vintage that normally would have been picked in July or August came off the vines two days before Thanksgiving -- about three weeks after Napa's weather-delayed harvest ended.
In an industry where "hang time" is cherished for adding complexities to flavors, the implications are profound, especially for folks anxious about the global impacts of climate change on historic wine-growing regions.
"If this can help incrementally improve the quality, it means big money for growers, especially in a global market," said Joe Bezerra, executive director of the California State University Agricultural Research Institute, which is helping to fund the project at Fresno State University.
Gu's immediate aim is twofold: to add complexities to the 150,000 acres of wine grapes grown in California's San Joaquin Valley, home to 44 percent of the state's crop, and to open marginal areas to higher-end production.
"I hope it doesn't get any hotter in Fresno," he said, "but it doesn't matter because we know now that we can manipulate the growing season."
Because grapes grown here ripen so quickly, growers are forced to harvest before the acids and tannins that contribute to a truly great wine can fully develop. Gu, a professor of viticulture, appears to have solved that problem by pruning off the first crop of clusters in June, which forces the vines to generate a new crop just as the weather really heats up in July.
In September, the 2011 grapes entered veraison, turning color as they began ripening, which is just about the time Fresno's brutal summer temperatures begin to subside. The grapes then spent long weeks on the vine during the time the weather in Fresno more closely matches the summer temperatures in Napa or along the Central Coast.
"This is exciting," Gu said Tuesday, as he watched a crew of students bundled in winter jackets ferrying bins of cabernet sauvignon to the school winery. "We're picking wine grapes in Fresno at Thanksgiving. That has never happened before."
The grapes are better than the commercial crop the school harvested during the summer because the sugars, acids and pH are balanced within optimal levels, he said. The grapes harvested Tuesday have enough sugar to make a wine with slightly over 13 percent alcohol, on par with France but surprisingly light compared to most "big" California wines that hover near 15 percent.
But considering that some Central Valley grapes get so overly ripe that wineries have to add water to bring down the sugar levels, the Thanksgiving harvest is remarkable.
Gu's efforts to force a later harvest have taken many forms. He first tried manipulating irrigation to slow the ripening, and when that failed he tried canopy management -- using the vines to shield grapes from the blazing sun.
"Nothing made a difference because the overriding factor is temperature," he said.
Then he remembered that some fruit growers in the tropics can get two crops a season, so he decided to try forcing a later harvest on a block of campus grapes.