‘Challenging’ weather conditions may benefit grape crop

Scott Swanson

The clear, sunny skies last week prompted a rush to get grapes harvested in Willamette Valley vineyards, including those at Marks Ridge Winery near Sweet Home.

“Everybody in the valley is scrambling to get their grapes harvested,” Janet Westly, who has co-owned Marks Ridge since 2005 with her husband Jay, said Thursday as she waited for a picking crew to arrive. “With storms coming in we’ve decided to get them in now.”

The cool weather this summer may not have helped home gardeners but it could be an advantage to Oregon wine grapes, according to researchers at Oregon State University.

“Often the most challenging weather conditions produce some of the finest wines,” said Steve Renquist, an OSU Extension horticulturist who works with the wine industry in the Umpqua region.

In monitoring heat units—a calculation involving time and temperature—Renquist pointed out that most wine growing regions in Oregon are about on schedule with last year for ripening, and the northern Willamette Valley is a bit ahead of 2010. In areas where heat units are fewer, less sugars develop. But the complexity of wine comes from many attributes of the fruit, not simply sugar content.

“In cool years similar to this in the past, the wines have developed delicate, crisp flavors because they’ve retained some of the acid in the fruit,” Renquist said. “Of course, we won’t know about this year until the grapes are harvested and the wine is in the bottle,” he added.

Wine grape growers are accustomed to dealing with challenging weather, according to Patty Skinkis, an OSU professor and viticulture specialist. Cool temperatures this spring delayed flowering in the vineyards, she said, so everyone expected a late harvest. However, Skinkis’s research has quantified that fruit set was significantlyhigher than normal for most of the region’s wine grapes, resulting in big clusters of grapes.

“The growers prepared well for the season. They thinned fruit and pulled leaves to open the canopy in order to maximize grape quality, hasten ripening, increase fruit color, and reduce the potential for Botrytis bunch rot.” Skinkis said.

Furthermore, results of her fruit quality research in 2010 indicate that last year’s cool season led to higher than normal development of phenolic compounds and other quality parameters, despite being lower in overall sugar accumulation.

The Westlys grow Pinot Noir, Riesling and Gewürztraminer grapes in their 17 acres of vineyards at the crest of Berlin Road on Marks Ridge.

“It’s not a stellar year,” Janet Westly said. “It was just too wet and cool all summer long – very much like last year.

“We probably won’t have a nice big Pinot Noir this year. We might have a good rosé. We’ll crush the grapes immediately and make it like white wine, in stainless steel instead of oak barrels. We have options. We can let it go to dryness or keep it sweet.”

The Westlys did not harvest their grapes in 2010, deciding that the summer had been too cool and that they could “hang tough” with the inventory they had on hand.

“That would have been fine if this was a normal year, but now we’ve had two years like that.”

Unlike sweet table grapes, the quality of wine grapes relies on development of a complex array of flavors as well as the balance between sugars, acids and phenols, according to James Osborne, the Extension enology specialist at OSU. This is especially true of the cool season varieties that are iconic of the Willamette Valley.

“Pinot noir, for example, can develop more complex flavors and aromas with a longer, cooler season that often results in lower sugar levels,” said Osborne, whose research focuses on how microorganisms impact flavor development during the wine-making process. “It’s always a matter of balance, and some of the best vintages come from cooler years.”

Pinot Noir grapes wait to be transported into the winery on Marks Ridge last week.

“The challenge and the attraction of Oregon wines are that they are not easy to make, but the potential for excellence is always there,” Osborne said.

Neil Shay, director of the Ore-gon Wine Research Institute, sees potential for excellence in this year’s vintage. “I’ve visited vineyards all around the state, and the fruit that’s hanging now looks excellent,” he said.

Westly said that vineyards in California have been harvesting late as well this year, for the same reasons Oregon growers are. She said that Marks Ridge may buy grapes or grape juice from other growers to make wine.

“There’s a variety of things at our disposal that we can do,” she said. “For white wines we can get the grapes in from the vineyard and have wine in six months. Red wines have to sit in barrels for a year, year and a half.”

She said she and her husband might take a tasting trip after the harvest is in, and if they like what they’re tasting, they can buy those grapes later on.

“We’ll get something. Then we’ll go out and get some different wines,” she said.

“That’s what vintage is all about. You have some great years and then you have some off years. You just don’t want too many in a row.

“It’s just kind of fascinating. It’s not necessarily happy, but it’s not all bad news.”

OSU writer Peg Herring contributed to this story.

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