Sspring is hard youIme of the year for Andy Fles, the vineyard manager of Shady Lane Cellars, a vineyard and winery in Suttons Bay, northern Michigan. Spring is when the buds burst happens: when the brown, scruffy vines burst into greenery. Grape buds emerge from the winter vine in delicate shoots and begin the process of producing this year’s vintage of wine grapes. For Fles and other vineyard managers, bud burst signals new life, new seasons and endless possibilities for this year’s vintage.
Bud break typically occurs in May, Fles says, depending on heat buildup. “When that happens, we are all very nervous because of the frost.” In Michigan, the first days of warm spring are almost inevitably followed by another hard freeze – and sometimes several. “Once the green tissue is out, it’s very sensitive,” says Fles. “It’s not like the leaves of an apple tree that can tolerate sub-freezing temperatures. If we reach 32 [degrees] or below for more than an hour or two, then we’re going to have some damage there.
In recent years, bud burst has been getting earlier and earlier. But because frost often still follows, winemakers like Fles have to perform acrobatic mental calculations to try to predict their harvest. The average air temperature, monthly precipitation, and sun exposure averages in Michigan’s climate all change rapidly. Climate change is affecting how Michigan winemakers grow grapes, how they manage their vineyards, and even the varieties of wine they produce. Vineyard managers need to find creative ways to account for climate change, including adding more varieties suitable for longer periods of heat. But while that might sound like great news for wine production in the state, extreme weather conditions like those forecast can make it difficult to plan from seed to bottling.
Over the past 60 years, Michigan’s grape growing season has shrunk by almost a month. This adds growing degree days – the accumulation over a year of average daily temperatures above a threshold temperature for a particular crop. That’s good news for winemakers in one of the country’s northernmost wine regions. Not good news for Michigan grape growers is the increased weather volatility predicted by climatologists in the coming decades.
Paolo Sabbatini is an associate professor of horticulture at Michigan State University. He has spent nearly 20 years working with Michigan grape growers, studying the short- and long-term effects of climate change on the industry. For Sabbatini, the big takeaway is that Michigan will remain, as he dubs, “constantly inconsistent.” The polar vortices of 2014 and 2015 devastated the cultures of the region; Sabbatini and climatologists predict winter weather will become increasingly volatile and harder to predict, with more violent storms and polar vortices.
Michigan is home to five distinct United States Vineyard Zones, or AVAs, each with unique soil, microclimate, and growth patterns. All of these, as well as most of the state’s fruit orchards, are on the west and north coasts of the state. There, the high volume of water leads to more frequent snowfall. This snow helps insulate from extreme cold by creating a blanket that retains heat and protects sleeping vines. “Winters are very, very complicated [to predict] in Michigan, because the temperatures depend on many different factors related to the enormous amount of water around us,” says Sabbatini. “So harsh winters are winters when the lake freezes: you lose the lake effect, because there is ice on top of the lake. throughout the season.
In 2017, Sabbatini and his colleagues compared historical weather data from Michigan and Napa, California since 1970. While the average temperatures of the two regions over the course of a year have increased dramatically, Michigan’s temperatures have oscillated sharply. In Napa, temperatures varied from ideal temperatures for viticulture by 10% in each direction. That is, the average temperature remained 10% cooler or 10% warmer than the ideal temperature for growing wine grapes. In Michigan during the same years, the temperature variation from the ideal was 40% in each direction.
“It’s the constant inconsistency,” says Sabbatini. “Yes, we are on a streak of more heat. But the streak doesn’t come cohesively, like in Napa Valley and other areas, but with a lot of variability. It’s a bit like the financial market. It’s still going up, but through a lot of different bumps. You always win in the long term, but in the short term you can lose. And it’s Michigan time.
It’s not all bad news for Michigan’s growing wine industry. A longer growing season means more chances for high quality wines. Advances in weather forecasting and vine breeding and cultivation can mitigate some of the worst effects of storms. Shady Lane’s Fles even sees advantages for Michigan growers over growers in other areas: “We have varieties that are well suited to a cooler climate, and I think we’re going to stay that way for quite a while.” We don’t see the same kind of things you see in the West, where there’s a lot of talk about whether the region is getting too hot for Pinot Noir.
As wildfires and extreme heat waves ravage West Coast wine regions, Fles notices a new group of fruit growers and grape growers moving into Michigan. One of the main advantages of Michigan winemakers is all around us. “We have water security here,” says Fles. Thanks to this lake effect, Michigan grape growers don’t have to rely on irrigation, which saves a lot of money and bodes well for future grape growers. Fles recently helped a Colorado market gardener move to Michigan; this decision was motivated in large part by the change in access to water.
As the industry grows, Michigan winemakers are making increasingly complex and flavorful wines. Certified sommelier Liz Martinez is group director of beverage and hospitality for Backbone Hospitality Group, which owns Mink, Marrow, Folk and The Royce in southeast Michigan. Since moving to the state five years ago, she has been impressed with the rapid evolution of the quality and variety of her wine. Long known for its sweet Rieslings, Michigan now produces competitive, quality red wines, including Cabernet Franc and Pinot Noir, two rather temperamental grape varieties. “If you’re a smart winemaker,” says Martinez, “you can find a way to adapt and find the varieties that are right for the region. Michigan could soon stand out.