Rain during harvest season can do a lot of things to wine grapes — good and bad.

Rain during harvest season can do a lot of things to wine grapes — good and bad.

At best, rain can slow down the development of sugar in the grape while allowing flavor to reach an optimum level. At worst, rain can split the fruit, diluting the flavor and delaying ripening. Rain can even enable mold that may ruin an entire crop.

With 2.76 inches of rain, the Rogue Valley had its second-wettest September on record, exceeded only by 4.22 inches in 1977. But a long, hot and dry summer, followed by September's unusual weather — brief storms followed by days of warmth and wind before the next storm — created nearly ideal conditions for Southern Oregon wine grapes.

Randy Gold of Pacific Crest Vineyards is happy with the results. Gold is a vineyard manager for many local growers and sells his own grapes to winemakers.

"Most of our fruit came off the vines early, before the rains hit," says Gold. "With the later-ripening fruit, the rains slowed down the development of sugar, the 'brix,' and the subsequent cooler, dry weather allowed the flavors to mature."

Brix is the standard measurement of sugar content in grapes. The higher the sugar content, the higher the alcohol level during fermentation.

"We're having a normal October," says Gold. "We're getting some serious hang time, improving flavors. Growers with fruit hanging now all over this region have smiles on their faces."

Dan Marca of Dancin Vineyards in Jacksonville concurs.

"A lot of our varieties ripened early and were harvested before the rains came," says Marca. "Our chardonnay and pinot noir escaped the rain and cold. We had rain on the last day of harvest, and it only delayed picking by 24 hours."

Bill Steele of Cowhorn Vineyards in the Applegate says he saw virtually no effect from the rain. "Our grapes ripen later and our harvest was only delayed a week. The rain and cold slowed down the sugar and allowed the flavor to develop."

Eric Weisinger of Weisinger Family Winery and Paula Campbell Brown of Dana Campbell Vineyards, both located in Ashland, noted that the rains at the end of September gave the growers a bit of a break after an unusually early September harvest.

"The early ripeness had everyone scrambling," says Weisinger. "The rains slowed things down. The best weather is usually in October, and now we have it."

"Grape growers always make the best of it," says Campbell, "And, in this case, the best is very good."

Michael Moore of Quail Run Vineyards supplies grapes to more than 40 winemakers in Oregon and produces wine locally under the South Stage Cellars label. Compared to the Willamette Valley, he said, Southern Oregon's harvest weather was mild.

"The Willamette Valley was hit very hard," Moore says. "I've talked to people who had six inches of rain in two days. It was cold and drizzly for most of the month. Many growers I spoke to had a lot of splitting. The brix level dropped and before it could come back, it rained again and got colder. Then, when the grapes did ripen, everything had to be harvested quickly, and a lot of growers couldn't get a crew in time."

Moore says he has received calls from Willamette Valley wineries looking for fruit to add to their own grapes because their crop was so damaged.

Gold, however, says he has spoken to some Willamette Valley growers who came through the rains just fine.

"They are used to rain during harvest," Gold says. "They have nerves of steel, they just wait it out."

Roberta Kent is a freelance writer living in Ashland.