A bounty of plump grapes is making its way from the vineyards into tanks and barrels, as the 2012 grape harvest hits the halfway point in Sonoma County.

Weather has been ideal so far, and yields for many varietals have been 15 to 20 percent larger than expected, grape growers said. Pinot noir, a local specialty, is among the most abundant.

The excess grapes arrive after two years of shortages, and at a time when inventories are low and demand is high for California wine.

"Everybody lost their tail last year, and to a point the year before, and this year everyone has a chance to recoup some of that," said Ned Hill, owner of La Prenda Vineyards Management based in Sonoma. "Everybody wins in a good crop year."

The main problem facing grape growers and wineries now is figuring out where to put all the fruit, as nearly everything ripens at once.

"The heat last week really put things in gear," said John Clendenen, owner of Clendenen Vineyard Management in Healdsburg. "The winemakers are bearing the brunt of all this. They're slammed. Any winery big or small, they're all struggling, because so many things are getting ripe at the same time."

In early September, cool temperatures slowed the development of sugars in the grapes, delaying the ripening of pinot noir and chardonnay in the Russian River Valley, said John Balletto, president of Balletto Vineyards and Winery. But then, temperatures heated up, quickening the pace.

"I have not seen a crop of this size ever," Balletto said. "Everything's kind of plugged up, so if you don't have that extra outlet it's kind of tough."

Balletto and other winemakers have had trouble finding available barrels, as incoming crops have exceeded estimates made just a few months ago.

"There's not a (used) white barrel available in California that I know of," Balletto said. "We were just looking to buy 100 white barrels, and we had no luck."

Typically, grape growers estimate crop sizes early in the season, based in part on the number of clusters growing on the vine. But the globes have grown fuller and rounder than expected.

"It's like last year we were picking lemons, and this year we're picking grapefruits," Hill said.

The glut of grapes is enabling wineries to replenish inventories at lower prices, a welcome change for many that have dealt with pricing pressure in the past year. Most of the harvested grapes are committed to wineries through contracts that were set far in advance. Once ripened and picked, the extra grapes have to go somewhere fast, and with so many coming on the market, they're being sold at discounted prices.

"It varies dramatically," said Pete Opatz, vice president and senior viticulturist at Silverado Premium Properties. "The larger the winery, the deeper the discount. They can be as high as 35 to 40 percent off the contracted price. There are isolated cases where yields are so large, and overages so significant, they move in and buy grapes literally at Lodi prices."

That's led some growers to custom-crush their own extra grapes instead, to sell the wine on the bulk market where they might make more money.

"We haven't chosen to custom-crush any extra stuff yet, but some people have discussed it," Hill said. "We're just getting to the point where it's tough to sell."

Gio Martorana, winemaker and owner of Martorana Winery, which produces about 1,500 cases of wine a year, said he is planning to crush about 15 tons of excess merlot grapes to sell on the bulk market.

"It's happening everywhere," he said. "A lot of people are going to be doing this."

Grape growers with early-ripening fruit sold their excesses, but as the harvest ground on, winery tanks filled up and prices on the spot market dropped. For example, excess grapes from a Russian River pinot noir vineyard that sold for $3,000 a ton under contract fetched $2,200 to $2,400 a ton on the spot market, said Glenn Proctor, partner at Ciatti Co., a San Rafael grape brokerage. After a few weeks, the price fell below $2,000.

Those one-time deals probably won't have a significant impact on grape prices in 2013, Proctor said.

"When it comes down to it, these wineries are still growing at 3 to 5 percent," he said. "They're going to need grapes."

Adding to the stores of bulk wine will help the California wine industry, which has depleted the supply after grape shortages in recent years.

Three years ago, there were 22 million gallons of wine listed with Turrentine Wine Brokerage, for all varieties across California, said Brian Clements, vice president of the Novato company.

"If you look at that same category, we're at about 4 million gallons now," Clements said. The current excess could push the total to about 6 million this year, he said.

In Turrentine's pricing observations, pinot noir from the Russian River pinot has been selling for at least $2,000 a ton, chardonnay has been selling in the "mid-teens," cabernet sauvignon in the "high teens" and merlot has sold at around $1,100 a ton, Clements said.

"Prices were getting pretty crazy, and the wineries were looking at greatly reduced returns, so I think this is just what we needed to go forward," Clements said.

Whether the weather will continue to hold is anyone's guess, and recent forecasts have called for light rains, which have largely spared North Coast vineyards so far.

"Things are going relatively smoothly to this point," said Steve Sangiacomo, partner at Sangiacomo Family Vineyards. "But things can change quickly in harvest. . . . We're just kinda keeping our fingers crossed that the weather holds out a little longer."

You can reach Staff Writer Cathy Bussewitz at 521-5276 or cathy.bussewitz@pressdemocrat.com.