Ravenswood was founded in 1976 in Sonoma Valley by Joel Peterson. Peterson is a microbiologist by training, but while doing immunology research in San Francisco in the early 1970s he began dabbling in winemaking. Because of his success with Zinfandel, he quickly became known as the godfather of Zinfandel, and single vineyard Zinfandels continue to be the estate’s flagship wines. Ravenswood owns about 15 acres of vineyards but acquires most of its grapes from a network of more than 100 northern California growers. The estate also makes Chardonnay, Merlot, Cabernet Sauvignon and various blends.
Sonoma County is not an AVA, but it is a commonly used informal designation for wines made outside of more specific AVAs within Sonoma, which is a large wine producing region just west of Napa Valley. Though Sonoma is often overshadowed by its glamorous neighbor Napa Valley, it has a long history of wine production. The area specialized in jug wine until the mid-20th century, when Sonoma producers took a cue from Napa and started improving quality. Unlike Napa, where Cabernet Sauvignon is king, Sonoma specialized in Chardonnay, Pinot Noir and Zinfandel, though excellent Cabs are produced too. There are at present 16 AVAs within Sonoma County, and, like much of the West Coast of the United States, new AVAs are created in Sonoma County with regularity. Some Sonoma appellations, such as the Russian River Valley, are renowned for Pinot Noir and Chardonnay.