Arroyo Grande Valley AVA
Arroyo Grande Valley was recognized on February 5, 1990 by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) as the state's 60th AVA based on the petition filed in 1987 by Don Talley of Talley Vineyards and William S. Greenough of Saucelito Canyon Vineyard for the establishment of the "Arroyo Grande Valley" viticultural area in San Luis Obispo County.
The valley is divided by a fog line produced by the cool maritime layer where Zinfandel, Petite Sirah and Rhône varietals are grown on the higher elevations near Lopez Lake and the cooler mid-valley vineyards being home to Chardonnay and Pinot noir.
[7][8] The mission at San Luis Obispo farmed the bottom lands in the valley from 1780 until 1842 when the Mexican governor granted "Rancho Arroyo Grande" to Zefarino Carlon.
The land was cleared and Henry planted Zinfandel and Muscat grapevines imported from Europe and purchased locally according to the Ditmas family.
The oldest winery in San Luis Obispo County, St. Remy, was also established in Saucelito Canyon in 1880 and produced wines until Prohibition.
The Arroyo Grande area is west of the Santa Lucia mountain range and experiences the moderating coastal influences.
The principal stream in the area is the Arroyo Grande Creek which meanders approximately 12 miles (19 km) in a southwesterly direction from the spillway of Lopez Lake to the Pacific Ocean.
The climate during the months of March, April and May is dominated by a strong onshore air flow bringing cold winds which delay early season growing and fruit set of the grapevines.
Because the Arroyo Grande Valley is shielded by the mountain range on the northwest side, the effects of the onshore air flow are moderated.
The fog usually burns back in the late morning hours, which gives a gentle warming in the afternoon, ideal for good grape quality.
The land is composed of sedimentary and volcanic soils over a layer of bedrock known as the Franciscan Complex which is uplifted oceanic and continental crust formed over 100 million years ago.
