Taking the Temperature - Grape Expectations
After 11 years as a coastal science and policy specialist in Boston, Chantal Lefebvre and her husband Mike Newman moved to Northwest Michigan in 2007 to be closer to family that’d recently relocated there. With no particular plans, Lefebvre thought it was her chance to reinvent herself. “I took some time off and got a job — really just to meet people — in a tasting room out on the Old Mission Peninsula,” she says. That, ultimately, led her down a path in wine.
In the years that followed, she worked at vineyards Left Foot Charley, Bowers Harbor, and Brengman Brothers, doing all aspects of the business, from the tasting room, to selling, to growing. She quickly learned that producing great wine in the region isn’t easy: Snow piles high from November to March, after all. Winter temperatures can rival those of Antarctica. For Lefebvre, the challenge became part of the draw. “I really fell in love with the work,” she says.
Lefebvre and Newman first sowed the fruits of WaterFire Vineyards in 2009, after purchasing the 26-acre farm property. Sandwiched between Lake Michigan and Torch Lake are WaterFire’s 10 acres of riesling, sauvignon blanc, and Grüner Veltliner. The fruit basks in those moderating bays, she says, which essentially softens and lengthens the transition between seasons: “It’s just a big buffer.” It’s a grape-growing sweet spot that the vinter has to work hard to maintain.
Michigan’s wines in general, particularly its rieslings, are garnering increasing attention and accolades: In 2019, Wine Enthusiast announced the state was “sailing toward world-class wine production,” giving 90 points-and-higher rankings to 16 affordable bottles. (The cheapest, at $13, was a 2013 riesling by Chateau Grand Traverse.) But Lefebvre and other grape growers face an overheating world that’ll eventually make their jobs much harder. That could affect the $5.4 billion Michigan wine economy that, according to a 2017 study, “directly creates nearly 28,000 jobs.” And it might also permanently alter the taste of Michigan’s wines — the bold fruit flavors — that seem on the cusp of breaking through to the big time.
Grape growers in the Midwest — Michigan, Ohio, Minnesota, Wisconsin — are largely spared from the raging wildfires that threaten vineyards on the West Coast. But they do have to navigate how the region’s increasingly erratic weather patterns and changes in the environment will affect their product — the timing of ripening, alcohol content, acidity, and even the color of the wine. “If you’re able to achieve better physiological ripeness, then you’re going to have more complexity in your wine, which of course is sort of the unique fingerprint of your wine,” says Lefebvre. “Getting that balance just right between sugar and acid can be extremely challenging certain years.” In extreme years, temperatures dropping low enough during the winter or climbing high enough in the summer could kill the vines.
It’s complicated to tease out the exact effects of climate change in the Midwest. A 2019 study by researchers at Michigan State University and the University of South Alabama found that a changing climate has helped Michigan literally branch out into the wine industry in some ways. Paolo Sabbatini, co-author of the study, found that the time grapes have to ripen has dramatically increased over the past few decades. And that leads to increased production: Maria Smith, a viticulture outreach specialist in the College of Food, Agricultural, and Environmental Sciences at the Ohio State University, says that “pushing back the first day of freeze [later] into the fall ... benefits us a lot more in terms of actually being able to get the fruit ripe.”
But it’s not just output that’s affected; climate changes in the past decades have led to a vastly different landscape that increases the areas where grapes can be grown. Growers will have more options “in different spots in Michigan, in different sites, in different soil, in different locations,” Sabbatini says. The reason for this shift is rising average temperatures over the past few decades, with warmer springs and more frost-free days. A lot of growers saw “a lot of damage through the winters,” Sabbatini says, referring to injuries suffered by buds and canes (the shoots that house the buds and leaves) that are brought on by frost. In late winter and early spring, fluctuating temperatures could also lead to deacclimation and early bud break; that can result in severe injury and even vine loss. But now, Sabbatini notes, winters are getting warmer. Though Michigan has long been a cool-climate region, “it’s possible in the near future we’ll need to change classification from cool climate to warm climate,” he adds.
Cool-climate regions like the Midwest mainly grow what we call American–French hybrid grapes, crosses between the classical Vitis vinifera — which makes up the bulk of Michigan’s wine grape yield — with native American varieties, which tend to be very cold-hardy. But the shift is creating an opportunity to introduce varieties that previously wouldn’t grow in these areas. “From that standpoint, climate change actually benefits us quite a bit,” Smith says. “I’m thinking about petit verdot, tempranillo — grapes like that. Those are super-late varieties that you would think of in places like Texas.”
But this doesn’t mean that Bacchus is smiling down upon fields across the Midwest. Bud breaking, flowering, and ripening are all extremely temperature-dependent, and growing grapes in this region is already fraught with its own challenges, from sub-zero temperatures in the winter to high humidity in the summer. A warming climate will only exacerbate the area’s volatile weather.
One of climate change’s biggest threats to the wine industry is rain. According to Sabbatini, high rainfall creates a wet and warm climate favorable to fungi and other pests. What’s worse, grape varieties common in cool-climate viticulture — like chardonnay, pinot noir, and riesling — are very sensitive to fruit rot, introducing malodorous smells to the wine. Even if new grapes can be planted, this is a huge risk to an existing, known crop.
Another concern is how a warming planet has led to the northern migration of insects, like the spotted lanternfly. Swarms of the invasive insect have already decimated vineyards in Pennsylvania and Delaware. “It can be really devastating to great crops,” Lefebvre says. “They’ve only found dead ones in Michigan thus far, but we need to keep an eye out. They’re extremely difficult to control.”
More frequent visits from the polar vortex are also another potential consequence of a warming world. This is best understood as a large pocket of very cold air, typically the coldest air in the Northern Hemisphere; the frigid air can find its way into the United States when the air mass is pushed farther south. A devastating polar vortex in the winter of 2014-2015 decimated most of the Midwest’s vines, says Smith. In Ohio, the fruit had major winter injury; many growers completely lost their vines. Smith says that event was a “staining memory” among Ohio grape growers — a portent to a new climate reality requiring new tactics and decisions. The industry’s response was to start planting hybrids developed to thrive in cold-climate regions. This is happening while the region’s climate is only getting warmer.
That’s precisely what Minnesota grape grower Tom Plocher has embarked on: developing new wine grapes for the Midwest in the era of climate change. Plocher has been a tour de force in the cold-climate wine world since the 1980s. “Back in the ’80s and ’90s we didn’t even really think about it that much as a problem, and now we seem to have the threat of a late frost in May, after the grapes have started growing, like every other year,” Plocher says. As a private grape breeder, Plocher provides his grapes to winemakers throughout the country and internationally.
In the long term, Plocher says, some of the concerns that crop up for grape growers thanks to a changing climate can “probably be solved with breeding.” Since 1996, Plocher has been working to develop cold-hardy grapes in his acreage near Hugo, Minnesota, in the Twin Cities’ northern suburbs; he’s been conducting research in the field since 1983. So far, he’s developed three cold-hardy grapes: Petite Pearl, Crimson Pearl, and Verona. The goal for all three grapes is to hold dormancy and delay bud break, to protect the product from spring frost, as well as ensure the grapes stay hardy through the winter.
According to Plocher, most current cold-hardy wine grapes have thin skins. “If they suddenly get 2 inches of rain in a short period of time, the berries will swell up and the skins can’t contain them,” he says. “They split right at the stem.” Once split, the berries are open to insect pests and fruit rot. “You can end up with a mess,” he adds.
Right now, Plocher is working on a selection of grapes with very tough skins — “literally twice as thick as all my other varieties,” he adds. “The birds won’t even try to peck holes in it. I will be on my second generation of breeding thick-skinned grapes this summer ... and I should get something out of that that’s pretty good.”
Plocher isn’t alone; researchers at the University of Minnesota and Cornell are also developing seeds for vineyards in cold climates. And though vineyards facing climate change may indeed need to invest in new varieties of grapes, that’s a tall order. “Of course, the desire is to deal with it without having to replant your vineyard” — a heavy expense of time and money, he adds.
Back in Michigan, Sabbatini is working with grape growers in the area on how to delay bud break by pruning vines in alternative ways. The best way for growers to determine how much bud injury they have had in a given winter is by cutting buds open with a razor blade. According to Sabbatini, vines pruned very late in the season usually start spring growth slightly later than those pruned mid-winter dormancy.
“Sometimes one week or 10 days is enough to escape the spring frost,” he says. “Everything that we do now in the vineyards is try to adjust to the variety that we’re growing, the techniques that we’re using in pruning, and the techniques that we’re using during the summer to manage the canopy, to face the reality that we need to face.” Sabbatini is also working with the state’s wine industry using new mapping tools to fine-tune the search for optimum vinifera sites.
Other grape growers, like Lefebvre, have tapped into creative techniques like focusing on sustainable grape-growing — practices that are environmentally sound, socially equitable, and economically feasible. At WaterFire, they focus their sustainability practices in several areas, minimizing their impacts to air and water and focusing on energy and soil conservation and recycling. They also practice integrated pest management.
“I spent many years of my life talking about the impacts of agriculture on the environment,” says Lefebvre. “So, it didn’t make sense for me to just get on board and as a conventional farmer.” From the get-go, she wanted the business to focus on becoming a sustainable operation. In 2017, WaterFire Vineyards became the first vineyard in the Midwest to achieve certification from the California-based organization Sustainability in Practice (SIP). “It’s a lot of work to maintain it, but it’s worth it,” she adds.
Tucked between vines and forest and just one mile from Torch Lake, WaterFire Vineyards is well situated for growing wine. But, as Lefebvre says, “unless we get a handle on climate change, we can only do so much. ... Severe weather events are just going to be something that we have to deal with. Whether that means changing the types of grapes that we’re growing, that’s probably going to play into it.”
“Our reputation is certainly going to be bolstered by higher, higher temperatures,” she says. “But all of the other craziness that goes along with climate change ... those are things that we worry about.”