The harvest of raisin grapes in California’s Central Valley is nearing an end, with growers reporting better yields than last year and expecting better prices.

Harvests of Thompson seedless grapes, using both traditional paper drying and overhead trellis systems, should mostly be wrapping up this week, says George Zhuang, Fresno-based University of California Cooperative Extension viticulture advisor. “Last year was such a disaster, with low tonnage,” he tells Western Farm Press. “This year is a little better. Compared to the historic average, it’s a little less than average.”

This year’s early-season bunch count averaged 33 clusters of raisin grapes per vine, up from 27 last year, but below the historical average of 37, according to Kalem Barserian, general manager and chief executive officer of the Raisin Bargaining Association. He expects a crop of about 250,000 dry tons “if everything goes right,” he told American Vineyard magazine. As of July, the industry had delivered 220,000 tons, which means the carryover supply will be the lightest in decades.

ACREAGE DECLINES

Bearing acreage of grapes grown for raisins has been on a steady decline, from 273,047 in 1999 to an estimated 149,197 last year. The shrinking acreage is pushing up prices; Barserian says he has heard instances of companies offering growers two-year contracts at about $2,000 a ton, which would be significantly higher than the $1,100 per ton growers got in 2016 when the industry was trying to pare down an oversupply of California raisins.

Growers were looking to rebound in 2018 after a disappointing 2017 crop, which started with a low cluster count and continued with weather problems. Widespread damage from a series of summer heat waves in 2017, including one over the Labor Day weekend, were followed by a pair of rainstorms right in the heart of the September harvest.

Thunderstorms dropped as much as a half-inch of rain in some vineyards just as grapes were drying on the ground, causing millions of dollars in losses for growers. Rain can make raisins drying on paper trays dirty or moldy, sometimes requiring extra processing or reconditioning at the packing plant to clean them. Also last year, the heat and some instances of bunch rot combined to weaken grapes and leave them more vulnerable to rain damage.

This year, some growers had a rough time with powdery mildew, which can affect quality and yield, and there were reports of bunch rot, Zhuang says.

SMOOTH HARVEST

“Generally speaking, this year has been a pretty smooth harvest,” he says. “The only concern right now is, we’ve been getting such cool temperatures.”

Afternoon temperatures in Fresno since Sept. 12 have been topping out in the high 80s, although highs this week were expected to creep back up into the mid-90s, according to the National Weather Service.

“It’s been so mild,” Zhuang says. “People were concerned there’d be a delay in drying some varieties. But overall it should be smooth.”