It’s virtually impossible to go anywhere within this relatively small, roughly 50x8-km (30x5-mile) valley without bumping into someone who’s somehow involved in the business of producing or selling wine, or selling the wine country lifestyle. One grand winery after another lines Highway 29, and further east, the parallel and slightly more bucolic Silverado Trail – each a marvel of some form of classic architecture from French château to Persian palace, as varied as the immigrants who settled California. It’s clichéed, but if Walt Disney had dreamed up the Magic Wine Kingdom, it would surely have resembled the Napa Valley. As far as wine tourism goes, this is the place to be; nobody does it better. While other regions in California can rightfully claim a longer wine-growing history, the Napa Valley has become the epicentre of luxury California wine and the wine country experience.
Although Napa was already greatly admired as a wine region in the 19th century – there were over 140 wineries operating by 1889 – it was the 1960s that witnessed the birth of the modern era. Several of today’s most celebrated wineries were established then, the likes of Heitz Wine Cellars, Robert Mondavi Winery, Diamond Creek and Stag’s Leap Wine Cellars, among several others.
There are 16 sub-AVAs with the Napa Valley AVA, though few are purely volcanic. Although the entire region was once covered with volcanic rock, subsequent uplifting and depression, sheering, slicing and erosion have exposed different strata of underlying bedrock in a near-random pattern, like a pack of wild children digging their fingers into a layer cake.
It’s geology-defying to generalize, but the Vaca Range on the eastern edge of the Napa Valley is predominantly volcanic in the upper elevations, from the Coombsville caldera all the way north to Howell Mountain. The top ridge of the Mayacamas Mountains that separate Napa and Sonoma is largely marine sediments of the Franciscan Formation on the Napa side, and more volcanic on the Sonoma side in the vicinity of Mt Veeder. But the Mayacamas become more uniformly volcanic as you move north to Spring Mountain, Diamond Mountain and Calistoga, and into the upper Knights Valley and Alexander Valley.