The idea of American AVAs comes from France. In France, the government tells growers which grapes they can grow in which region. Our government regulates the area but we can grow whatever we want. Something about a market economy and free will...
AVAs range in size from 26,000 square miles to 1/4 square mile, and these have evolved over the years. For instance, within sunny Napa Valley, smaller AVAs have risen to the top of the quality heap, producing exceptional fruit. Places like Oakville, Rutherford and Stag's Leap are known for their Cabernet Sauvignon and Merlot since the weather and soil are perfect for those grapes. So, if you see one of these AVAs on a wine label, it's good shit, even at the high prices you'll pay. But don't shy away from the general Napa Valley AVA. Its diversity in weather and soil lends itself to outstanding growing conditions for varieties like Chardonnay and Zinfandel.
Saddled with plenty of AVA regulations, grape growers have to be vigilant. If a Sonoma winery prints the "Sonoma Valley" AVA on the label, 85 percent of the grapes contained in the bottle must come from that region, or the winery could face serious fines (although how they enforce that, I cannot imagine). Same goes for the smaller appellations within Sonoma, like Russian River Valley or Dry Creek Valley. But, if they can't muster enough fruit from the Russian River, they can still put Sonoma Valley on the label.
Russian River Valley is famous for two types of grapes that excel in the volcanic clay soil and cool climate in that area: Pinot Noir and Chardonnay. Russian River Zinfandel also rocks. So if you see the Russian River appellation on a label, it's a good bet the wine in the bottle is pretty damn good. Dry Creek Valley grows juicy, flavorful Zinfandel grapes but they do a phenomenal job with Sauvignon Blanc. Los Carneros, an area straddling both southern Napa and Sonoma Counties, and Chalk Hill are reliable bellwethers for great Pinot and Chardonnay.
Venture south to Santa Barbara and you'll find Santa Maria Valley, Santa Ynez Valley and Santa Rita Hills AVAs. This region is a perfect example of why AVAs should exist. The weather in Santa Barbara can differ 20 degrees from one area to the next, so they created smaller AVAs within the Santa Barbara region to designate the difference. Cooler Santa Maria Valley and Santa Rita Hills produce full-bodied, yummy Pinot Noirs and Chardonnays; the warmer climate of Santa Ynez creates deliciously ripe Syrah.
Maybe it's not exact yet, but our AVA system is making progress towards letting us know where the good stuff is. That way, we can follow our tastebuds to the checkout counter.
Rombauer 2001 Carneros Chardonnay $28.
Baileyana 2001 Edna Valley Sauvignon Blanc $15.
Groth 2000 Oakville Cabernet Sauvignon $50. 1/2