Tired of the heat? So are Idaho grape growers, and for good reason.

Posted at 6:18 PM, Sep 06, 2022

EAGLE, Idaho — Most farmers would agree: when relying heavily on Mother Nature, no two years are the same.

That's the case this year for Idaho grape growers dealing with the impacts of an unusually cool and wet spring followed by a record-breaking hot summer.

Mark Pasculli with Rolling Hills Vineyard in Eagle is now playing the waiting game as most grapes appear two to three weeks behind schedule. He's spending his days pruning plants to prioritize energy into ripening the grapes with the best chance of maturing before the inevitable first fall freeze.

Most grapes at his Eagle vineyard are still bright green. He said typically by now, they'd all be purple.

While wine grapes do appreciate warmer weather, Pasculli said scorching summer sun can actually burn fruit, impacting its flavor, and as conditions soar into triple digits, the fruit can burst.

Still, he said the biggest heat-related setback comes with extended periods of temperatures above 95 degrees, essentially delaying the ripening process. Like humans, he explains, the plants aren't the most productive during 100-degree days, basically waiting for cooler temperatures to continue their ripening process.

The way things look right now on his Eagle property, Pasculli's grapes are still about six weeks away from reaching the right sugar levels for red wine.

"At this point the biggest concern is you get into early October and you get a hard early freeze and then that kind of changes the whole game because they will not be ripe enough at that point," Pasculli said. "If it's early enough and hard enough, you basically say goodbye to 2022."

However, harvesting is already underway elsewhere in the valley. In southwest Nampa, grapes grown specifically for sparkling wines are ripe for the picking.

Courtesy: Jake Cragin

"The high acid really makes for a great sparkling wine; so that's why we pick so early," Hailey Minder with 3100 Cellars said. "The acids are still coming down in the grapes as the sugars are increasing."

Minder said their ripening process was still a bit out of the ordinary this year, impacted mostly by the colder than usual temperatures early in the season.

Jake Cragin, with Winemakers LLC, points to mid-April when we saw snow and freezing temperatures across the valley.

"Things started early and then got shut down with all the cold weather and kind of paused," Cragin said. "So we ended up starting a lot later than usual."

Back in Eagle, Pasculli hopes the remainder of the growing season is "average" at best, with temperatures peaking in the 80s and avoiding an early frost.

Even if an October freeze forces an early harvest, he has a few backup plans in place. What would typically be harvested for red wines may turn out to be cases of rosé. And if the natural sugar levels are only slightly off, they can sweeten the product during the wine-making process.

Rolling Hills Vineyard

Idaho's wine industry has been steadily growing over the last few decades. Fifty years, ago there was only one winery in the state. Now, there are more than 70.

In 2020, Idaho grape growers harvested 2,100 tons of grapes, producing 315,000 gallons of wine, according to the Idaho Wine Commission.

Experts say the area is ideal for growing grapes because of the rich, volcanic soil, desert climate, and direct access to water.

Get to know more of Idaho's wine industry: