McDowell Valley was designated and approved as an American viticultural appellation on January 4, 1982, one of the earliest viticultural regions so designated by the United States Bureau of Alcohol, Tobacco and Firearms (BATF). It is one of only two single winery appellations in California. Among other features of the valley, the BATF designation recognized the distinctiveness of McDowell’s history, microclimate, topography and soils. The Federal Register summarizes the BATF designation in this way:
“McDowell Valley is a natural, sheltered valley surrounded by mountain ranges, including some which rise sharply to elevations of over 2,500 feet above sea level. McDowell Creek drains the valley and flows into the Russian River system. There is an upper elevation contour of 1,000 feet around the valley which effectively contains an area of ‘gravelly-loam’ alluvial soils. The surrounding slopes are composed of non-alluvial upland soils which are unsuitable for vineyards.
The valley has temperatures consistently warmer during the spring frost season and cooler during the summer growing season than most Mendocino and Lake County areas. The name originated with an early settler, Paxton A. McDowell, who settled in the area about 1852. Historical use of the name for the area dates from 1872., (T.D.-ATF-97)”
The valley is flanked by deep canyons to the east and west which provide conditions to draw breezes inward from the Pacific Ocean to moderate temperatures. This coastal maritime weather pattern produces warmer temperatures during the frost season when the vine experiences bud break and berry set; subsequent summer temperatures are cooler than surrounding valleys which allows a longer growing season. This inland coastal climate is particularly well suited to Sauvignon Blanc, Cabernet Sauvignon, Zinfandel, and Rhône varietals.