Cold-tolerant grapes developed by University of Minnesota researchers have sparked the doubling of the number of wineries in the state in the past six years.

It wasn't that long ago that Minnesota had no wine-making industry at all, the St. Paul Pioneer Press noted. But that has changed at this week about 400 peopled attended the Cold Climate Conference in St. Paul to learn more about growing grapes in cold regions to produce palatable wines, the news paper said Saturday.

"There's more and more demand for wine across the nation, and that's certainly true in Minnesota, which is one of the contributors to wanting to open a winery," said Ron Barnes, president of the Minnesota Grape Growers Association. "The wine-consuming public is becoming more and more aware of Minnesota wines, and the quality of the wines has increased dramatically."

Paul Hugunin, head of the Minnesota Grown program at the state Department of Agriculture compares the growth in the wine industry to that in craft beers.

"People want things that are local and that are unique," he said. "People want something with character, something unique and something local."

The Pioneer Press said agriculture researchers at the University of Minnesota have engineered grapes that are able to withstand cold winters and remain tasty. The university's cold-tolerant grape varieties are partly responsible for the birth of vineyards in every state in the union, including Alaska.

Barnes said Minnesota "wineries have figured out how to deal with the high acid that cold climate wines had."

Veteran grape grower John Marshall of Lake City noted "wineries are getting a little fussier, and that's a good thing."