Winemaking for William Ballentine Jr. has always been a family concern. He began his career tending vines owned by his father, who established Ballentine Vineyards at the foot of Napa’s Howell Mountain. The knowledge and experience he gained there—and through his work with other growers throughout the valley—now informs the wines of William Cole Vineyards, which Ballentine and his wife, Jane, established on a historic parcel in St. Helena, Calif. Here he continues to make and—in the case of his latest release—…