Bundled up against a chilly wind, Nan Bailly strides up to a trellis at her Hastings vineyard, snips off a bit of vine and shaves off its bark.

"That's what we want to see," she says, pointing to the exposed green tissue. The vine is alive and has made it through the winter.

Bailly repeats the process one row away and discovers the news isn't as good. This stem's brown interior means that section of vine is dead.

This winter's intense and persistent cold has laid down an early challenge for Minnesota grape growers, including Alexis Bailly Vineyard, the state's oldest commercial winery.

Fueled by cold weather-hardy grapes — including varieties developed at the University of Minnesota — the state's industry has grown to about 45 licensed wineries, according to the Alcohol and Tobacco Tax and Trade Bureau. A federally funded university study found that the vast majority have sprung up in the past 10 years, and they contribute about $60 million in economic activity throughout the state.

Bailly grew up in the business, knowing she wanted to work in it even as her father, David, began planting the very first vines in the early 1970s. She took charge of the vineyard and winery after his death in 1990.

"I can't remember another winter like this, and we've been growing grapes here for 40 years," she said. It wasn't just the extremely low temperatures, but the length of the deep freeze, which can dehydrate vines.

For the past few weeks, Bailly has been out in the field, pruning vines and assessing winter damage. She'll know more in a few weeks when buds on vines begin to break open (or not). Right now, she believes the harsh winter killed off about 40 percent of the primary buds, the main producers of grape clusters.

That's similar to a preliminary forecast for grape growers statewide, according to Jim Luby, who directs the fruit-crop breeding program at the university. "It's pretty bad. We've had winters where the bud loss has been almost nought," Luby said.

Growers can work around heavy bud damage by pruning their plants lightly, said Ron Barnes, president of the Minnesota Grape Growers Association. "The strategy is to leave more [buds] on than you normally would. The overall vine will still be viable and have the capacity to actually ripen grapes," he said.

Growers in Minnesota have fared better than those in New York, where severe winter damage has prompted the U.S. Department of Agriculture to declare some of the state's grape-growing regions disaster areas. In Ohio, growers are expecting that some grape varieties may be a total loss.

In Minnesota, snow that came early and accumulated throughout the winter may prove to be a godsend because it insulated vines from root damage, which, unlike bud damage, can kill the entire plant. Since grapes need three to four years to mature, there is a lag when grapes have to be replanted before the fruit can be used.

"We were laying down the last of the straw to cover plants just before we got that ice storm in November, and then right after that the snow came," Bailly said. "The snow never left our vineyard until just a few weeks ago."

In addition to protecting the root systems of Bailly's cold-hardy grapevines, which are left up on trellises throughout the winter, the straw also covers the original French vines planted by her father.

Those plants, which were not engineered to withstand subzero temperatures, have to be taken down every year and covered. In the spring, they are uncovered and put back up onto the trellises. They are still under the straw, but Bailly thinks those vines may have come through the winter in better shape than the newer, cold weather varieties.

"Those have been the backbone of our vineyard," said Bailly of the older French vines. They account for about half the vineyard's 13 acres of plants.

Bailly's tasting room opened for the season this month, and she also recently began blending wine from last fall's harvest. That growing season also had its own set of challenges, starting with an extremely cold spring and a winter storm in early May. The season ended with heat and drought, which Bailly thinks may have added body to the final product. "So far I'm happy with what I've been tasting," she said.

Susan Feyder • 952-746-3282