Rockpile viticultural area. Seghesio Family Vineyards. As Zinfandel farmers in Sonoma County since 1895, we believe that Sonoma County contains several areas that grow world class Zinfandel. Rockpile, a narrow ridge some 1200 feet above Dry Creek Valley, is just one of those areas. Steep, well-drained hillsides with shallow, rocky topsoils provide for intensely flavored Zinfandel. Bonded winery 56. Alcohol 15% by volume. Produced and bottled by Seghesio Family Vineyards, Healdsburg, CA.