Heat wave suddenly speeds up SLO County’s grape harvest

Workers harvest grapes at night at Stone Corral Vineyard.
Workers harvest grapes at night at Stone Corral Vineyard.

The grape harvest is heating up on the Central Coast, both figuratively and literally.

Picking at many San Luis Obispo and Paso Robles’ vineyards is starting a couple weeks later than recent years, in part due to a cool early August, but speeding up now with this week’s heat wave.

“It wouldn’t surprise me if we get buried in ripe fruit in the next couple of weeks,” said Kevin Jusilla, owner and winemaker of kukkula wine in far northwest Paso.

That could mean labor shortages if demand for picking crews hits all at once, but heat spikes at the end of the growing season cause other problems as well, noted Kevin Sass, winemaker at nearby Halter Ranch Vineyard.

“I see a lot of vineyards in the county shutting down and turning red. Disease is starting to show itself from all this stress,” he said, noting the ranch saw five days straight of 100-plus temperatures with potentially another week of the same to come. The heat can also cause sugars to accumulate faster than the skins develop, leading to under-ripe flavors. “These factors make picking decisions tricky,” Sass said.

Paso vineyards are picking mostly white and reds for rosé so far, with harvest for most red grapes expected to begin after Labor Day and stretch through September. Around Edna Valley, many growers planned to start picking this week, though a few got started as early as Aug. 14.

Albarino from Jesperson Ranch Vineyard - Courtesy Niner Wine Estates
Piles of albarino grapes await processing after they were picked at Jesperson Ranch Vineyard. Niner Wine Estates

“It used to be that you routinely had Labor Day weekend off here, and that hasn’t happened since 2010,” said Fintan du Fresne, general manager and winemaker at Chamisal Vineyards. “However, this year is later than the past three years, which is a good thing.”

Expected yields are still all over the map, with some vineyards reporting more tonnage than the recent drought years, but many saying they are still slightly below average.

“The vines are very happy and look great, but I don’t think we will see a bump in crop yields until the 2018 vintage,” said Stephen R. Dooley, winemaker and proprietor at Stephen Ross Wine Cellars.

And many winemakers have noted that berry and cluster sizes are far smaller than usual.

“It is a very strange phenomenon that the berry size is so small considering the abundant rainfall,” especially compared to other rain-heavy vintages, said Kenneth Volk Vineyards’ Kenneth Volk, in his 40th vintage on the Central Coast.

“Though lighter in yield, we are very happy with the intense concentration in the berries,” said Edna Valley Vineyard winemaker Kamee Knutson. “We’re expecting bright flavors balanced by crisp acidity.”

The rain did help restore some soil and vine health, many growers noted, and spurred vigorous canopy growth — too vigorous in many cases, with the heavy leaf cover leading to problems with mildew in many areas.

The vines at Alta Colina Wine in the hills off Adelaida Road “came out of the blocks hell-bent on growing world-champion canopies — and pretty much got it done,” said co-owner/winemaker Bob Tillman. By the time they realized and began opening up the canopies, he said, the mildew had started to take hold. “We have been fighting a rear-guard action all season.”

Harvest at Paragon Vineyard - Courtesy Niven Family Wine Estates
Workers harvest grapes at Paragon Vinyeard. Niven Family Wine Estates

Off Highway 46 West, Barton Family Cellars/Grey Wolf also battled mildew all season. “We tried to be present in all our fields earlier this year to make sure things did not get out of hand,” owner/winemaker Joe Barton said. “Years like this year it’s paramount to make more inspections more often.”

Despite a few oddities, though, the wet winter and warm summer provided near-optimal growing conditions that growers are counting on for decent yields and good quality.

“This is about as ‘normal’ as we’ve seen for a long time,” said Nathan Carlson, general manager at Edna Valley’s Center of Effort Winery.

Sally Buffalo writes about wine, beer and spirits. Reach her at sallybuffalo@gmail.com or on Twitter or Instagram @sallybuffalo.

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