Oregon vintners are a nervous bunch these days. They're looking at one of their latest vintages ever in 2011. None of the major Pinot Noir producers expect to pick before Oct. 15, more than two weeks later than normal. Major rainstorms can start in mid-October, and a late harvest increases the chances of a washout.

The entire West Coast has had a late growing season this year, but Oregon's is particularly nerve-wracking. Perfect weather at flowering caused the vines to set a very large crop, but cool, cloudy weather in late spring and early summer kept the grapes from ripening normally. Most quality-oriented growers went through their vineyards and stripped down the crop significantly to encourage ripening of remaining bunches, but the vines had produced such large bunches that normal thinning still left potential yields of more than 4 tons per acre in many vineyards, 50 percent to 100 percent larger than normal.

“I took a picture of one bunch,” said Josh Bergström of Bergström Wines, pointing to a picture on his iPhone. “That one weighed about 425 grams." That's about double the usual size for Pinot Noir. "It’s a big crop and that’s making us nervous that we can’t get it all ripe before it’s too late.”

Vintners would welcome a big crop after the 2010 vintage, which produced very small yields, down 20 percent to 50 percent over the previous year in most vineyards. But heat accumulation figures through Oct. 3 were the lowest in decades. At one point the vines were a month behind normal progress, although warmer weather in August and September helped. “We had more degree days in August and September this year than we did last year,” said James Frey, owner of Trisaetum Vineyards. “The good news is we’re going to get well over 100 days of hang time, maybe as many as 115, which would produce great flavors, if a big rainstorm doesn’t ruin it.”

Oregon vintners don’t fear light showers, but big rainstorms can end a harvest prematurely, as happened in 1984. Forecasts are for mild weather with occasional showers for the next two weeks, but in the Pacific Northwest that can change quickly.