Following last year’s bountiful harvest, California’s raisin growers were expecting production to slip this year. But they didn’t think it would be nearly as much as their tray counts indicated when they were laying down grape clusters to dry in late August and early September.

“Because of the cyclical nature of grape vines, we were anticipating this year’s raisin crop would by substantially lighter than last year’s heavy crop,” says Steve Spate, grower representative for the Raisin Bargaining Association, based in Fresno, Calif. “Once we started picking the grapes, we were seeing production down anywhere from 10 percent to 50 percent. Early indications show yields this year may be off an average of around 20 percent, compared to last year. It’s frustrating.”

He cites several possible reasons for the unexpectedly sharp downturn in this year’s crop size: adverse weather in 2015 may have hurt development of the buds that gave rise to the 2016 crop; continued replacement of raisin acreage with more profitable crops, including tree nuts; water stress from several years of drought or from an irrigation system being off-line due to a pump or well repair; or some overlooked insect threat.

Growers who hand-pick grapes, which they place on individual drying trays in the field, can assess yield prospects by multiplying the weight of a typical tray by the number of trays put down to get the total estimated tonnage harvested from a field.

Predicting yields for machine-picked grapes is more challenging. In that case, growers can gauge production by the length and width of the continuous paper tray the equipment rolls out on the ground to hold the raisins as they finish drying.

“In some fields this year, the machines didn’t start laying paper until about a third of the way down the row,” Spate says.

While crop size may be down, the quality of this year’s raisin crop may be up.

“Sugar levels are coming along well,” Spate adds. “Early reports of higher sugar levels should equate to better quality raisins. Most of those growers are hopeful they can gain back at least some of what they lost in yields in the form of a better dry-down ratio as the grapes dry into raisins.”

In fact, accelerated sugar development, as a result of the lower crop load prompted some growers to begin picking their grapes before Aug. 20 to minimize the loss of ripe grapes falling on the ground. Normally, sugar levels in California’s raisin vineyards don’t begin developing fully until the last week of August. This year, the bulk of the grapes were picked from Aug. 29 through Sept. 15.

Unlike several years ago, growers should be able to find the workers needed to harvest this year’s raisin crop.

“I haven’t heard of any grower wanting a crew who wasn’t able to get one this season,” Spate says. “It wasn’t that long ago when growers would receive multiple promises from contractors for labor that didn’t show up.”

Meanwhile, as the cost of workers who pick raisin grapes and place them on drying trays continues rising, so does the number of raisin growers replacing crews with machines to bring in the crop, he says.

With machine harvesting, canes are cut two weeks in advance of harvest to allow the grapes to dry on the vine. Cutting the canes requires fewer workers than hand harvesting.

And, of course, machine harvesting eliminates the need for crews to place individual drying trays in the field and to remove the clusters and lay them on the trays.

Mechanization does away with an unseen cost of hand-harvesting, as well. “Growers pay a piece rate for each tray put down ahead of harvest,” says Spate, a raisin grower himself. “You could pay for putting down, say, 15 percent to 20 percent more trays than necessary, if workers don’t place the proper amount of fruit on each tray. It’s like paying a crew of workers for phantom trays.”

Passage of proposed legislation calling for a $15-per-hour minimum wage and over-time payment after 8 hours of work per day for agricultural workers could push more raisin growers to adopt machine harvesting practices, Spate adds.