Idaho winemakers hope 2021’s intense heat leads to intense flavors

Idaho saw its summer temperatures rise sharply in June and continue through the months of July and August with temps regularly over 90 degrees— often climbing to triple digits. Climate research has found higher average temperatures are increasing, and the EPA reports that heat waves have increased in intensity, frequency, and duration over the last fifty years. For Idaho wine growers, like Mike Williamson of Williamson Orchards and Vineyards, the heat of the past few summers is a growing concern. “I kind of obsess a little bit over the 10-day forecast,” he says. “So, if something’s on the horizon, we start taking action to get ready for it now.”

The new normal for a new generation

Located in the heart of the Sunnyslope Wine Trail, Williamson Orchards and Vineyards has been family-owned and operated for generations. Mike, who’s co-owner along with his sister Beverly Williamson-Mack and his cousin Patrick Williamson, has been in the game long enough to have nearly seen it all, but the intense heat of the past few summers is a new phenomenon.

For Idaho winegrowers like Mike and others, the potential impact is huge. Intense heat can affect the size of the grapes and the quantity of juice. When temperatures rise above 95 degrees, vines slow down and go into heat stress mode. This means they close the stoma on the leaves as tightly as they can to conserve their water. This slows down photosynthesis and slows the development of sugars in the fruit.

Balancing extremes

Finding the sweet spot between too much and too little sun is hard to achieve. “We need all the good solar days we can get,” says Mike. The more sun you have, the more photosynthesis and sugar production happens inside your fruit. Likewise, the less sun and lower temperatures, the less ripening and lower sugar production you’re going to see.

“That slows down the ripening and it pushes us back,” Mike observes. “So, we won't see the sugars develop like we need to,” he adds. And those delays invite an opposite yet equally threatening foe to the fore: unseasonably early frosts.

Still, if Mike has to choose between too little sun and extreme heat, he’ll take the heat any day. “As long as I’ve got water, I can deal with the heat.”

For the farmers of the Sunnyslope AVA, which is composed of dry, rolling hills and is best described as a ‘high desert’ climate, water is always the answer. The region experiences less than ten inches of precipitation between November and March, which is great for preventing mold and disease of the vines, but not so good for getting them the water they need to produce grapes.

So, early settlers tapped into the Snake River and created reservoirs to save the melt off from the mountains for irrigation. Snowmelt and irrigation canals do the rest—giving Mike and other neighboring wineries and vineyards (such as Ste. Chapelle Winery, Fujishin Family Cellars, and others) an incredible amount of control not just over the supply but also in crafting the flavor of the wine before the fruit is even harvested.

If water is one indispensable resource the winegrowers of Sunnyslope share, the other is communication. Says Mike, “The other growers and me, we've been all talking like, ‘What are you guys doing? What should we do? What can we do?’ And we've kinda been pouring on the water—at least half as much on top of what we normally do.”

Within our wine-making community, this type of banding together is not unusual under the best of circumstances. But in these times of changing climate, when peoples’ entire livelihoods are on the line, it’s more critical than ever.

“We rely on each other,” Mike describes. “We’re new enough and small enough that we’ve got to collaborate.”

He believes it’s part of an unspoken farmers’ creed to be there for each other. “There's going to be a day my truck is going to break down. So, I’m going to call my neighbor and say, ‘Hey, I’m in a pinch, can you help me out?’ And so, you kind of go back and forth like that,” he explains. “And dealing with something like this heat stress is the same. Because a lot of this, it’s out of the norm.”

He continues, “If we can share what we're doing, freely back and forth, we’re going to come up with better ideas for how to grow grapes and how to make the best quality wine in Idaho. And that desire to raise the best product is evident in that collaboration.”

Intense heat. Intense flavors?

So, what types of flavors can we expect from the class of 2021 vintages?

According to Mike, there’s a lot to be excited about. And perhaps there’ll be a few surprises too. “I do see a potential for 2021 to be a standout year for reds and intense flavors for whites,” he explains.

“We're starting to see the berries are swollen and they’re just starting to turn color,” Mike explains, “If we don’t get as many cells because they were stressed, and the plant was not able to make as much juice, that'll limit the maximum size that you can get. But that does give you a greater surface area to juice ratio. There's a lot of color, a lot of flavors, tannins, and different things that are extracted in the fermentation for reds that’ll really affect the wine flavors and quality.”

Another thing you may see is more acidity, depending on the return of cooler temps in September, which leads to that “very nice fruit balance that you can find in a lot of Idaho wine,” Mike says. “It all depends on what September brings us. That is really the finishing month for Idaho wine and for wine growing in a lot of the West. So, we all get to see what happens here in September.”

So, what we can see from the size of the berries offers some flavor clues. But for Mike and team, the real proof won’t come until well after Harvest, in January or February of 2022. “That’s when we get together with our winemakers and really digest what happened last year,” he states.

No pun intended.

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