Carlos Valle thins the grape clusters on pinot noir vines at the Gloria Ferrer Caves & Vineyards Circle Bar Ranch, near Sonoma, on Monday, August 5, 2013. Removing excess clusters allows the vines to produce a higher quality of grapes for winemaking.(Christopher Chung/ The Press Democrat)

Cool temperatures delay harvest in Sonoma County

Cool weather throughout Sonoma County has slowed the pace of grape ripening, bringing relief to winemakers who were rushing to prepare for an early harvest.

In warmer regions like Dry Creek and Alexander Valley, many growers are still anticipating an early harvest. But in cooler regions, winemakers are pushing back the date when they plan to pick grapes, and heading for a starting time that's closer to normal.

Temperatures across Sonoma County fell just below average in late July and early August. The lows ranged from 47 degrees to 52 degrees overnight, while the highs ranged from 77 to 80 degrees, according to Press Democrat weather records.

"It was pretty spectacular with fog burning off slowly in the hills in the Russian River," said George Rose, spokesman for J Vineyards & Winery. "Fog burning off at 11 a.m. or noon, that's the classic gloomy August. And it's perfect for grape growing."

Growers at J, typically among the first in Sonoma County to crush grapes for sparkling wine, had considered starting harvest today. Instead, they're postponing for about a week.

"There's absolutely no rush to pick the grapes," Rose said. "The slowdown is not a serious issue. It's almost a relief, because I think everyone wanted a little more time on the vine."

Gloria Ferrer Caves & Vineyards had been scheduled to start harvest on Wednesday, but decided to postpone picking until either the weekend or Monday, said Steven Urberg, winemaker.

"This cool weather has really slowed things down," Urberg said. "I'm looking at the rate of maturity over the last week ... Usually we expect to see 2 degrees of sugar in a week at this time, and I'm seeing closer to 1 degree."

The slowdown has brought a measure of relief to the industry for a number of reasons.

"Most wineries are still bottling," said Saralee Kunde, longtime grape grower and treasurer of the Russian River Valley Winegrowers. "They're trying to get last year's wine into bottles, so that's really pushing it for a lot of wineries, especially those that are relying on a mobile bottling line."

"And the longer hang-time is better for the fruit," because it develops more flavor and complexity as it hangs on the vine, Kunde added.

Temperatures in the Russian River area have been falling to 48 at night, and the air has been "drippy" in the mornings, she said.

"You're using windshield wipers just because there's a heavy dew," Kunde said.

That presented mild mildew problems for some growers, but preventive measures like sulphur spraying kept the problems at bay, said Duff Bevill, founder of Bevill Vineyard Management.

"We had one block that had some, but we took appropriate action," Bevill said. "In this particular case, we solved the problem by just doing our normal fruit thinning. We instructed (crews) to look for mildew while doing normal thinning. So that block is fine now."

Bevill may begin harvesting sauvignon blanc grapes at the northern end of Dry Creek Valley at the end of next week, he said.

Francis Ford Coppola Winery may begin harvesting sauvignon blanc grapes in Alexander Valley around Aug. 19, said Lise Asimont, director of grower relations.

Asimont tasted cabernet sauvignon grapes in a vineyard Monday and was excited at how the flavors had progressed. The "greenness" of the taste had begun to melt away, which usually happens later, she said.

"It's one of those great years that the flavor development is happening in concert with the sugar ripening," Asimont said. "When the cabernet is ripe and it has enough sugar in it, the flavors at that time are going to be outstanding if we're starting out where we are now. I'm stoked."

News Researcher Janet Balicki contributed to this story.

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