'Consumers buy with their eyes first,' market says; size second only to taste

By SEAN ELLIS

Capital Press

EMMETT, Idaho -- A study that seeks to find ways to increase the berry size of organic table grapes grown in Idaho holds promise for the state's conventional table grape industry as well.

Halfway through the two-year project, Rocky Fence Vineyard owner Mike Medes has already met several size goals of the $17,000 study, which is financed by a specialty crop grant provided by the Idaho State Department of Agriculture.

"For conventional growers, the (emphasis) is really on the size of the grapes," said Medes, who grows table and winegrapes. "The techniques we used can be used by conventional growers as well; it can help them a lot."

Idaho's table grape industry is relatively small and struggling to grow and the state's organic table grape industry is even smaller.

But Medes and others familiar with the study believe the results could be used to help the industry expand.

Brian Frost, owner of Sunriver Produce, the sole marketer of table grapes in Idaho, said grape size is extremely important to consumers.

"Behind taste, it's the most important factor for them," he said. "Consumers buy with their eyes first."

Medes started by listing the average current size of four grape varieties in Idaho -- Emerald, Alborz, Glenora and Red Globe -- and asking distributors and brokers what they considered the optimal size to be.

The size of the trial berries this summer were verified by University of Idaho Horticulture Educator Tony McCammon and study partner John Davis, a commercial grape grower.

Medes used seven different techniques to increase berry size and found that repeated spray applications of gibberellic acid was the most effective way of maximizing berry sizes.

The acid is a natural growth regulator that uses a naturally occurring acid in grape seeds to stimulate growth.

The first-year results were impressive, he said, but more work needs to be done during the second year to achieve the study's main goals, which include producing the maximum berry size on two-pound clusters that fit into the standard two-pound bags for packaging.

Emeralds, which have been growing to an average of 17 millimeters in Idaho, performed the best. While the trial goal was 19 mm, they averaged 21 mm.

"That's significant; it's a sizable difference in berry size," Medes said.

While the size goal of 19 mm was met for the Alborz grapes, Davis said the clusters did not color well.

A new goal of 20 mm has been set and the emphasis next year will be on reaching a full color with the larger berries.

The sizing goals for the Glenora grapes fell just short, but Medes said the project results indicate they should be able to handle a more aggressive sizing methodology and he believes they can reach the size goal of 19 mm.

The Red Globe trial grapes responded negatively to the sizing methods used in the study and Davis and Medes agreed they should be removed from the project.