Are Idaho grapes going up in smoke?

Posted by Idaho Wine Commission on Aug 19, 2021

As you read this, the Dixie Fire in Northern California rages on, having scorched more than half a million acres of land and becoming the second-largest blaze in California history—its noxious smoke unfurling as far east as Denver, more than 1,000 miles away. For Idaho wine growers, like Mike Williamson of Williamson Orchards and Vineyards, the heat and smoke of the past few summers are 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. The intense heat and smoke of the past few summers is an entirely new phenomenon.

“It seems in recent years especially, the smoke and the heat are kind of going together,” he observes. “When we get into this time of year, or even a little earlier, like mid-July, there are threatening conditions.”

Climate research has found higher average temperatures are increasing the length of the fire season and the number of places where fires can occur. Currently, California fire officials are reporting more than a dozen active wildfires across the state, and more than 100 wildfires burning across the western U.S., including in the gem state.

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.

Smoke taint, which occurs when vineyards are exposed to smoke, can add a burnt, cigarette-like flavor to the fruit. What’s more, it doesn’t just affect the health of the grapes. The well-being of local farmworkers is also at stake.

Balancing the elements

Luckily, for now, at least, the worst fires have spared Idaho. On the contrary, in a strange twist of fate that only Mother Nature can pull off, you could say the smoke has worked to our advantage a bit. “For the past several years, we’re about to get into triple digits, and then the smoke rolls in,” Mike explains. “And it kind of has a mitigating effect on the temperature. So they say it’s going to be 105 and it ends up being only 98—which is still hot, but the solar intensity is decreased because we have that high cloud cover.”

And because of the location of the fires (further to the West) and the way the wind patterns move out of the Northwest, “the really yucky taste that can get into the fruit just falls out along the way. It’s probably three days old by the time the smoke gets to us.”

So, for now, the smoke taint hasn’t been a major issue. Its effect on solar radiation, however, is a different story.

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 that come from, say, too much smoke in the air, the less ripening and lower sugar production you’re going to see.

So, while the smoke can blunt recent extreme temperatures, which is good, it also can filter out too much of the sunlight vines need to develop. “That slows down the ripening and it pushes us back,” Mike observes. “So, we won't see the sugars develop like we need to,” says Mike. And those delays invite an opposite yet equally threatening foe to the fore: unseasonably early frosts.

Lesser of two evils

Still, if Mike had to choose between toxic smoke and extreme heat, he’ll take the heat any day. “With smoke taint, there’s not much I can do,” Mike says. “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, since we know all is not lost, and that our wines won’t all be tasting like ash and smoke, 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.

Sign up for more

Do you enjoy finding out new things about wine, and maybe a little something about yourself in the process? Then sign up to the blog and never miss another post, winemaker profile, and other exclusive content from the Idaho Wine Commission.

Topics: Wine Education