MINNEAPOLIS - Two local winemakers are fighting a state law that bans the use of out-of-state grapes to make wine -- a regulation they say severely hampers their potential for economic growth.

The state law bans farm wineries from making wine unless a majority (51 percent) of the grapes used are local. Being a state that's in winter more than any other season, the law poses a challenge to local wineries.

"We only have 150 days of frost-free weather, where California has three times that," said Timothy Tulloch, of New Prague's Next Chapter Winery.

Along with Alexis Bailly Vineyard and the Institute for Justice, the two farm wineries filed a lawsuit Tuesday to fight the law, citing a violation of the Constitution -- and their right to engage in interstate and foreign commerce.

Nan Bailly said as Minnesota's oldest winery, they've struggled to keep up with the demand for their wines because of these restrictions.

In comparison, the wineries cited the ever-booming local craft breweries, which are not held under such limited restrictions and able to use hops grown in the Pacific Northwest.

The Minnesota Grape Growers Association hasn't taken an official position on the lawsuit yet.

But the group's president, David Mohn of Flower Valley Vineyards and Winery near Red Wing, says the novelty factor of Minnesota-grown wine should be protected.