(GreatNorthWestWine) - Last year’s heat meant lower tonnage in Washington state.

The annual wine grape report, released Monday, showed a mild decrease in the 2015 harvest, as the total tonnage dropped from 227,000 tons in 2015 to 222,000 tons last fall.

The most dramatic decrease was in Riesling, which had surged to a reported 50,500 tons last year and dropped to 44,100 tons last fall. Kevin Corliss, vice president of vineyards for Ste. Michelle Wine Estates, said he isn’t surprised the numbers are slightly down. He said the company’s estimates for Cabernet Sauvignon, Merlot and Syrah were down by 4 to 7 percent, depending on variety.

“With the heat, we saw smaller crops,” Corliss told Great Northwest Wine.

Ste. Michelle Wine Estates, which owns such wineries as Chateau Ste. Michelle, 14 Hands,Columbia Crest and Michelle Sparkling Wine, uses about two out of every three grapes grown in Washington.

Once again, Cabernet Sauvignon is king in Washington. The bold red Bordeaux grape jumped from 42,200 tons in 2014 to 47,400 tons last fall.

“That’s not surprising,” Corliss said. “That’s what’s been going in the ground in big acreage.”

Corliss said the company has been contracting a lot of Cabernet Sauvignon in the Horse Heaven Hills and Wahluke Slope, two of the state’s warmest areas. In the Horse Heaven Hills alone, Cabernet Sauvignon has gone from 2,917 acres in 2009 to 5,719 acres last year.

Statewide, Cabernet Sauvignon tonnage has more than doubled in the past five years, going from 23,100 tons in 2011 to 47,400 tons last fall.

Steve Warner, executive director of the Washington State Wine Commission, was pleased with the overall numbers, particularly Cabernet Sauvignon.

“It all seems to be consistently strong growth,” he said. “It’s not surprising with all of the Cab plantings that have gone on.”

Riesling dropping

Riesling had been on a strong run since 2000, but now it seems to be cooling off, in part because of lagging global sales. Chateau Ste. Michelle, which remains the world’s largest producer of Riesling, makes more than 1.3 million cases annually. Other producers, including Pacific Rim Winemakers, Charles Smith and Hogue Cellars also have large Riesling programs.

But Riesling tonnage has dropped considerably from 2014. The sleek white grape took a huge jump from 40,200 tons in 2013 to 50,500 tons in 2014. That dropped precipitously last fall to 44,100 – still the second-highest number in state history. That also makes it the strong No. 2 grape in Washington, just behind Cabernet Sauvignon.

Corliss said Ste. Michelle is no longer seeking new acreage for Riesling, as it has in the past 15 years. In fact, some Riesling is being grafted over to other varieties. He added that at the company’s estate Cold Creek Vineyard north of the Yakima Valley, some Riesling has been pulled out in favor of more Cabernet Sauvignon.

In fact, most white grape varieties saw drops in production last year:

• Chardonnay fell from 43,800 tons in 2014 to 42,000 in 2015.
• Pinot Gris dropped slightly from 9,100 tons to 9,000.
• Sauvignon Blanc slipped from 6,900 tons to 6,700.

Some of those numbers are related to the pervasive heat last year that saw record numbers of triple-digit highs in June and historically early harvests the first week of August.

Corliss and other growers reported lighter-than-expected cluster weights because the heat came many weeks earlier than usual.

Red rules in Washington

For the third time in four years, red wine grapes outpaced whites – and Corliss said that trend will undoubtedly continue for years to come. Last fall, all red wine grapes weighed in at 112,800 tons – the highest ever in Washington. Meanwhile, white grapes tipped the scales at 109,200 tons, the second highest in state history.

“If we have a normal year (in 2016), I would expect to see the reds take another big jump because a lot of acres will be coming online,” Corliss said.

Typically, wine grapes need three years from the time they are planted before they produce a sizable crop. So vines planted in 2013 will come into nearly full production this fall.

In the Horse Heaven Hills, 663 acres of new red wine grape vineyards were planted. Assuming they average three tons per acre, that would be nearly 2,000 tons of new grapes coming into production just from that appellation. That would be the equivalent of about 200,000 extra cases of wine.

That means more money for grape growers – and higher average prices for wine in Washington. Last fall, the average price of red wine grapes was $1,394 per ton, up from $1,336 per ton in 2014. By comparison, the average price for white wine grapes last fall was $844 per ton, down a bit from $856 in 2014.

The highest-priced white wine grape was Viognier at $1,082 per ton – and it was the only white wine grape to top $1,000 per ton.

Comparatively, all red wine grapes averaged at least $1,000 per ton. Grenache was the highest-priced grape in Washington for the third straight year, costing an average of $1,722 per ton. Mourvèdre was No. 2 at $1,649 per ton. Cabernet Sauvignon was No. 3 at $1,527 per ton (though Cab prices at top vineyards on Red Mountain can exceed $4,000 per ton).

Merlot saw a slight drop in tonnage last harvest, falling from 36,900 tons in 2014 to 35,200 tons last year. Syrah went up a bit, rising from 15,400 tons to 16,000 tons.

Overall, Washington’s “big four” grape varieties – Cabernet Sauvignon, Riesling, Chardonnay and Merlot – make up 76 percent of the grapes harvested in Washington.