Foster Road Vineyard, photo by Terry McCarthy
Remember the old Jack Lemmon-Tony Curtis-Marilyn Monroe movie “Some Like it Hot”? Well, winegrowers tend to like it Cool: not frigid cool or even chilly cool, but ‘not too hot’ …cool. Although we require plenty of summer sunshine and warmth to ripen our grapes, scorching heat can shut down grapevines, sunburn or shrivel grapes and ripen fruit prematurely.
Over the past several years, some in the climate change field have predicted that prime winegrowing regions like Napa Valley might soon be too warm for premium-quality wine grapes and that areas historically too cool for viticulture—like England or California’s far northern coastal countries—might become the new sweet spots for grape-growing.
Mother Nature apparently has not been reading these Chicken Little reports, however, because Napa Valley has had five consecutive cooler-than-normal vintages, beginning in 2005 and continuing through 2009. (A cool spring this year delayed budbreak and bloom by 10 days and summer was mild with few heat spikes.)
“Since 2004, degree days (a UC Davis measurement of heat by region during the growing season) in Rutherford have decreased,” says Cakebread Cellars Viticulturist Toby Halkovich. “What the climate change studies don’t address is the role of fog and soil in cooling vines. As inland areas get hotter, more fog is drawn into coastal valleys,
expanding the marine influence.”
Toby cautions that short-terms weather patterns do not constitute climate trends and that shifts generally occur in 20–to–30–year blocks. The Napa Valley Vintners Association has commissioned a study reviewing weather records in our region over the past 150 years, which should provide a broader perspective for assessing climate changes and effects.
In the meantime, Cakebread Cellars is focused on human methods of keeping things cool, such as harvesting at night, which keeps the fruit fresh and less prone to oxidation, making for better wines. Night harvesting also provides safer conditions for our workers, an important consideration.
“We harvest as much as we can at night,” Toby says. “It’s an invaluable tool that provides us with great flexibility. By starting our crush activities earlier in the day, we pick and process more fruit at optimum ripeness levels and protect our workers from extreme heat.”
Using boom lights that straddle four vineyard rows and provide light from all directions, our night harvest crews get started about 1 a.m. in our Napa Valley vineyards and as early as 8 or 9 p.m. in our Anderson Valley, Mendocino County vineyard. The goal is to have the fruit to the winery by 5 a.m. for crushing. (For a glimpse of our night harvesting operations, go to our website www.cakebread.com and click on the tab “Virtual Visit Video Clips”.)
As of mid-September, all our Sauvignon Blanc grapes had been picked, and a slice of Chardonnay as well. Toby reports that the fruit was in excellent condition, with no heat stress, and plenty of fresh, concentrated flavors. In other words, 2009 is looking like another very cool Cakebread Cellars vintage.
