Frog Tree Vineyard, a small, three-acre plot, is located in Coombsville. The Coombsville appellation is a crescent-shaped section of the foot- hills of the Vaca Range, where alluvial soils cover volcanic ash from Mt. George with cobblestone-strewn layers of rich, gravelly loams. This very temperate micro-climate allows the grapes to ripen slowly and steadily. Coombsville wines can often be recognized by their soft but significant tannins, which provide excellent structure.