Winter Weather Advisory – OR NOT?

 In CGT Blog

Winemaker Addresses Harsh Weather Concerns

It’s a well known fact that weather can severely affect the outcome of a grape harvest. Northern Michigan wineries have winters of all varieties, and in the past 40 years, CGT has always found a way to make the best out of each challenging scenario. Will the harsh winter weather affect local Michigan wine? Are wineries concerned about possible negative outcomes? Chateau Grand Traverse’s winemaker Bernd Croissant answers these logical questions about harsh winter weather and its affects on our vineyards.

As of mid-February, Old Mission Peninsula had received over 100 inches of snow accumulation for the winter total. That’s already 7 inches above the seasonal average: not that we needed proof of the extreme weather conditions. In Northern Michigan, we’ve become accustomed to hours (even days) of shoveling, layered clothing, and lots of snow days. Just as we’ve gotten used to the weather, so have our grape vines.


Vines in the winter at Chateau Grand Traverse

With winter temperatures hovering around 5 degrees for a majority of the season, concerns about vine damage have risen among the general public. “We can easily adjust to the weather by pruning. The situation is much worse when the temperatures vary greatly causing a cycle of melting and freezing.” We give credit to our founder, Ed O’Keefe Sr., for planting our vineyards strategically in 1974. This placement allows our vineyards today to have consistent snow cover, currently between 2 to 3 feet deep. “The good snow cover insulates the ground under the snow. The ground is still measured at 32.9°F, which at above freezing is perfect,” Bernd notes. Northern Michigan is prone to very unpredictable winters, sometimes causing temperature spikes as high as upper 50’s even 60’s with rain, with severe drops into the single digit temperatures to follow. These situations pose a much larger threat to the grape harvest.

“So as long as the ground doesn’t freeze, we can protect our nutrients and the vines.” As long as we have snow cover protecting the vines, our winemaker and vineyard managers are happy. The science behind viticulture explains the positive outlook.  With consistent temperatures, vines are able to preserve sugars and other nutrients. When a vine freezes and thaws, the grapes convert sugar to starch; once the vine freezes again, starch is converted back to sugar. Each time this conversion occurs, the fruit loses sugar content.

“Winter isn’t over, but we are optimistic so far,” says Croissant. The vines will be fine pruned in the spring, and at that point any potential bud damage will be accounted for. “It could be perfect.”

In reality, it’s too early to make any assumptions. Taking in samples too soon will not do you any favors. Our grapes are currently dormant, and they must slowly get accustomed to warmer temperatures.


Winter view at Chateau Grand Traverse

Although currently optimistic, it’s crucial to be cautious. “If I knew what grapes we would have I’d be looking into my crystal ball. Nobody knows. There are so many variables.” The situation right now is more favorable than past years, but we always prepare for the worst.  “As we say in Germany: you shouldn’t praise the day before the evening is over. So far it’s good, winter came early but we have constant snow, and lots of moisture.” And although challenging at times, we surely cannot complain about the view.

Click here to read more on the potential damage to buds this year according to growers in New York, Michigan, and Ontario. CGT President Eddie O’Keefe III reiterates the “cautiously optimistic” outlook on this year’s harvest.