Dunnigan Hills AVA
Dunnigan Hills is an American Viticultural Area is located in the Dunnigan Hills, in northwestern Yolo County, California. The wine appellation was established on May 13, 1993, as the nation's 119th, the state's 64th and the county's third AVA by the Bureau of Alcohol, Tobacco and Firearms, Treasury after reviewing the petition from Ron McClendon, winemaker of R.H. Phillips Vineyards, proposing a viticultural area in Yolo County named "Dunnigan Hills."
The Dunnigan Hills viticultural area is a group of low, rolling hills running in a northwest to southeasterly direction for about and at the widest point, the hills are about wide located in the northwest portion of Yolo County. The wine region has a Mediterranean climate that is less prone to frost than other parts of the Sacramento Valley. The largest winery in Dunnigan Hills was R.H. Phillips with its estate vineyard among the area's of cultivation. R.H. Phillips was eventually bought by Constellation Brands who relocated the winery facilities to Lodi, to the south, but still maintains the original vineyards. The plant hardiness zones are 9a and 9b.
History
The area's indigenous population mostly left by the 1860s. The Spanish missions did not settle in this part of the State, nor did Spanish settlers. The first non-native settlers of the area were western Europeans. According to Larkey, the Dunnigan Hills was settled in the 1850s and 1860s by German families who raised grain and livestock. In 1856 a post office was established in the town of Antelope, which was located south of the Colusa County line, just east of the Dunnigan Hills. In 1853, A.W. Dunnigan settled in Antelope and opened a hotel which was known as Dunnigan's. In 1876 the Northern Railway was extended to Dunnigan's hotel and a town plate was recorded for the town of Dunnigan and a Dunnigan post office was opened. The near-by hills soon were known as the Dunnigan Hills. Grape growing began in the Dunnigan Hills in 1861 when the Orleans Hills vineyards was planted by Jacob Knauth. In 1993, there were two wineries and six vineyards cultivating in the Dunnigan Hills.Terroir
Topography
The Dunnigan Hills rise out of a part of the Sacramento Valley which isnearly flat, varying only between above sea level. In contrast to the surrounding valley floor, the Dunnigan Hills viticultural area consists of low, rolling hills, which rise to an elevation of about above sea level. The hills are crossed by streams that flow west to east out of the Coast Range. On the west, the Dunnigan Hills drop to an elevation of approximately before the transition to the steeper, higher slopes of the Coast Range begins. The terrain in the Coast Range rises rapidly to, with peaks which are even higher.
Climate
The Dunigan Hills viticultural area is warmer in the summer and winter than the Coast Range highlands to the west. The petitioner states the area is also less prone to frost damage in the spring than the rest of the Sacramento Valley because "the hills and streams provide better air drainage than that found on the valley floor to the north, east and south of the Dunnigan Hills." This air drainage also makes the Dunnigan Hills cooler than the surrounding valley floor in summer.Soil
The predominant soils in the viticultural area are the Corning-Hillgate association, well-drained, gently sloping to moderately steep gravelly loams orloams on terraces, and the Sehorn-Balcom association, well-drained, gently
sloping to steep silty clay loams and clays over sandstone. Soils outside the area include the Dibble-Millsholm and Positas associations in the foothills of the Coast Range to the west, and the Yolo-Brentwood, Rincon-Marvin-Tehama, Capay-Clear Lake and Willows-Pescadero associations on the valley floor to the north, south and east.