Alisos Canyon AVA

The marine-influenced climate is also the basic viticultural feature of the Central Coast AVA. The climate of Alisos Canyon is affected by cool marine air which travels into the area via the drainage system of San Antonio Creek. The AVA is located approximately 25 miles (40 km) from the Pacific Ocean and is situated in a transitional region, between the cooler coastal regions and the warmer inland areas. Growing degree day accumulations within the Alisos Canyon are higher than those of the regions to the northwest and southwest, which are closer to the ocean, and lower than those in the more inland regions to the south and east. The region due north of the AVA also has higher growing degree day accumulations due to its location east of ridges and hills which trap warm air and block cool marine air from entering the region. According to the petition, the AVA's location is a “Goldilocks Rhone Zone,” meaning that temperatures are neither too hot nor too cold for growing Rhone wine varietals such as Syrah, which is the most common varietal grown in the canyon.[3][4]

Soils within the Alisos Canyon AVA are primarily derived from weathered sandstone and shale. The most common soils are the Paso Robles Formation and Careaga Sandstone, which comprise 63 percent and 13 percent of the total soils, respectively. High calcium content from shale pebbles increases the thickness of the skins of red varietal wine grapes, which in turn increases the color and tannin levels in the resulting wine. High sand content provides excellent drainage for vineyards, thus reducing the risks from certain pests such as nematodes and phylloxera. The low clay content of Careaga Sandstone soils reduces the uptake of nutrients and reduces the vigor of the vines, resulting in smaller grapes with a higher skin-to-juice ratio than grapes of the same varietal grown in different soils with higher clay content. To the north of the Alisos Canyon, within the Santa Maria Valley, the soils have sandier top soils. South of the Alisos Canyon, the soils are characterized by Metz fine sandy loam. To the east, the soils are primarily derived from serpentine and chert. To the west of the AVA, the soils are described as deep, sandy soils of the Shedd, Chamise, and Point Sal Formation series.[3]