Interest in Ohio wineries and vineyards has grown along with the industry, with the state's number of licensed wineries doubling in the past five years. The supply is keeping up with demand: Ohio's 148 wineries produce more than 1 million gallons of wine per year, with the largest operations producing up to 200,000 gallons annually and the smallest about 5,000, said Christy Eckstein, executive director of the Ohio Grape Industries committee.