New Wrinkle for Raisins: Dried-on-Vine Method

Pity the poor raisin. It starts life as a middle-class grape and never attains the social status of its cousins: Chardonnay, Cabernet Sauvignon and others destined to become fine wine.

But it may soon get a boost. University of California researchers taste-tested the sun-dried delights and asked consumers whether they preferred those dried traditionally on paper trays to those dried on the vine. They found that the two methods produced subtle taste differences and preferences among raisin eaters.

Can raisin snobs be far behind?

“I could see someone doing raisin tasting at Whole Foods or a recipe calling for a certain kind of raisin based on taste,” said Matthew Fidelibus, a researcher at the University of California’s Kearney Agricultural Center in the Central Valley city of Parlier.

The testing -- which looked at variations in fruitiness, chewiness and color -- may offer California’s $333-million raisin industry a new marketing angle to exploit.

Although California growers produce nearly all of the nation’s raisins and about 40% of the world’s supply, they are just now bouncing back from a slump that saw record low prices from 2000 to 2003, Fidelibus said.

Large crops and low demand brought prices down, said Karla Stockli, spokeswoman for the California Raisin Marketing Board. During the 2004 to 2005 season, when supplies stabilized and demand grew, farmers made $1,210 per ton, Stockli said.

Grape experts tested the raisins with 120 raisin eaters recruited at UC Davis and found widely divergent fancies.

“The differences were fairly pronounced,” said Hildegarde Heymann, a wine expert at UC Davis who worked on the testing.

Researchers found grapes that had been dried on the vine were fruitier, softer and lighter in color. The ones dried on trays were a bit more sour, chewy and stickier.

And many liked them better.

“I think a raisin should have a certain amount of sweetness and caramel. The [dried-on-the-vine] raisins have the sour tannin flavor that you catch in some wines. I don’t care for it,” said farmer Earl Rocca, 78, who has grown raisins in Fresno since 1950.

“There will probably always be a market for tray-dried raisins, which is good for a lot of the mom-and-pop operations out there,” Fidelibus said.

Many of the 4,500 growers in the south San Joaquin Valley would not be able to afford to switch over to vine-dried grapes, he said.

About 90% of raisin farmers grow the Seedless Thompson, a grape that doesn’t lend itself to on-the-vine drying. Growers would have to tear up their grapes and replace them with varieties such as those tested, the Selma Pete and the Fiesta.

And there are other drawbacks. Grapes on the vine take longer to dry, about a month versus as few as 10 days for those on paper trays, exposing them to potential rain damage.

About 55,000 workers are needed to harvest the region’s 350,00 tons of grapes each year, Fidelibus said. And immigration crackdowns have made it harder for farmers to put workers in the fields this year.

Although growers that can afford the machine to harvest grapes can reduce their need for workers, the industry is notoriously old school.

Raisins in California have been made in much the same way since the industry started about a century ago. Workers have cut the grapes in the summer and, since the 1960s, have laid them out on paper trays. Before that time, grapes were dried on more expensive wooden trays.

Dried-on-the-vine experiments began about 40 years ago, but it wasn’t until recently that larger producers such as Kingsburg-based Sun-Maid Growers of California mechanized about 20% of its crop.

For several years, the company has offered a relatively small supply of vine-ripened raisins, available only through the online company store, said Barry Kriebel, Sun-Maid’s president.

The No. 1 use for raisins is in other products such as cereals, cookies and snack bars.

Even the industry’s advertising doesn’t stray too much from the establishment.

It was only this year that the bonneted 90-year-old Sun-Maid girl became animated for the first time in a national ad campaign, explaining the ingredients for raisins: grapes and sun.

Fidelibus said he and others would continue researching raisin tastes.

“Maybe it won’t happen tomorrow, but some day people may be looking for the perfect raisin to balance out a sweet pastry,” he said.