Since the first edition of A Guide to North Carolina's Wineries in 2003, the state's wineries have nearly tripled in number. Tar Heel grapes are grown in the sand of coastal islands, on mountains so steep that tractors slide down them, and everywhere in between. The winegrowers include scientists, farmers, teachers, computer geeks, and "wine bums." They make or sell their wine at idyllic country estates, in converted gas stations and barns, and in...