American Viticultural Area, commonly referred to by its acronym AVA, is the geographically based classification system used in the United States to delineate specific growing regions. Unlike classification systems employed elsewhere in the world that impose clear limits on varietals that may be used, crop yields or ripeness levels, AVAs are generated according to topography, microclimate, soil composition and, in some cases, elevation. Boundaries of growing region are also required to be depicted on US Geological Survey maps.
A source of confusion and debate with the system lay in the fact that many AVAs overlap and in some cases, certain AVAs are entirely contained with other AVAs. For example, in Sonoma County, portions of Green Valley and Chalk Hill regions (along with a section of the proposed Freestone area) are located within the Russian River Valley AVA. Sections of the Green Valley and proposed Freestone area are also located within the Sonoma Coast AVA.
The system, now overseen by the Department of the Treasury Alcohol and Tobacco Tax and Trade Bureau (TTB), recognized Missouri’s Augusta AVA as the first American Viticultural Area in 1980. Since that time, close to 175 AVAs have been established, with well over half of those contained within California.
For a wine to be AVA designated on the label, at least 85% of the grapes used must have been grown with that region.