Chiles Valley Soil and Terrain
The Effect of Chiles Valley Soil on Zinfandel Production
The AVA is surrounded by steep hills that rise to about 2,200 feet. Cool air from these ridges settles on the valley floor each night. Hillside soils are extremely unfertile and made primarily of serpentine, sandstone and shale. Cool air from the tops of these hills is often drawn down into the valley’s vineyards. Because this cold air settles on the valley floor, the region’s topography causes temperatures to be quite a bit warmer on the ridgelines overnight.
Chardonnay has also found a home in the soils of Chiles Valley. It is usually made in a buttery, opulent style that is fuller bodied. It is much closer to an Oakville rather than a Carneros Chardonnay.
Soils on the steep ridges that surround Chiles Valley are made of serpentine chaparral. This soil is too nutrient poor and the topography too steep to plant grapes.
Chiles Valley runs southeast to northwest. The AVA only includes the narrow valley floor. The surrounding ridgelines are too steep to plant with grapes.
The soil on the valley floor is made of shallow and porous silty-loam and alluvial fans. By Napa’s standards, the soil is semi-fertile, but not so much so that vineyards over crop. There is a lot of ground water in the region which can be tapped for irrigation as necessary. There are numerous creeks and watersheds that drain the soil of Chiles Valley.
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