Number of wineries in Michigan. The state specializes in aromatic whites, especially riesling—along with pinot blanc, pinot gris, and gewurztraminer. Most wineries are clustered on the Old Mission Peninsula, a narrow finger of land extending into the center of Grand Traverse Bay. The Michigan wine industry began in the late 1970s when many of the most important wineries were founded. More than 2 million people each year now visit Michigan wineries.