California is a large, diverse wine region and is responsible around 90% of US wine production. Chardonnay is the dominant white grape and Cabernet Sauvignon the dominant red, with significant amounts of Merlot, Zinfandel and Pinot Noir also being produced. Rhone Valley varieties and red Italian varieties are also grown in the warmer parts of the region. It is divided into AVA’s (American Viticultural Areas). An AVA mark on the wine label means that at least 85% of the wine in the bottle comes from that area. California can be divided into 5 main viticultural regions running from the northern border with Oregon down to Mexico.
The Napa Valley, Mendocino County, Lake County, Sonoma County and the Carneros region are found north of San Francisco in the North Coast region. This is true Californian “Wine Country". The geology of this region has a huge influence on grape growing with the Pacific Ocean moderating the climate with sea breezes and sea fogs and the seismic nature of the area meaning that there is a diverse range of soil types and microclimates. 100 miles to the north of San Francisco is Mendocino County and Lake County. Due to the varied geology in these areas, there are both cool and warm spots amongst the lakes, mountains and valleys. As well as Chardonnay and Cabernet Sauvignon, delicate varieties like Pinot Noir and Gewurztraminer grow well in the cooler areas and Syrah, Petit Syrah and Zinfandel enjoy the warmer locations. There are a lot of small producers and a heavy emphasis on organic production. The Napa Valley is slightly inland an hour’s drive north of San Francisco and is arguably the most famous of the Californian AVA's producing particularly good Cabernet Sauvignon. Expect a rich wine with lots of depth, well-integrated tannins and intense aromas and flavours of black currant, ripe plum, black cherry and liquorice. It is a geologically active region so has a wide range of soil types and a Mediterranean climate with warm days and cool nights. West of Napa lying on the Pacific Coast is the slightly cooler Sonoma County which is more suited to growing Pinot Noir as well as Chardonnay and Cabernet Sauvignon. The Carneros AVA lies to the South of Napa and Sonoma Counties close to San Pablo Bay and has a distinct microclimate. Sea fog and cool breezes from the bay moderates the climate making it suitable for Pinot Noir and sparkling wine production.
The Central Coast extends south from San Francisco Bay down to Santa Barbara. In the north, you find the cool climate Santa Cruz Mountain AVA which produces good Pinot Noir, Chardonnay and Cabernet Sauvignon. Heading south you find Monterey County. Plenty of Chardonnay is grown here alongside Pinot Noir, Cabernet Sauvignon and Merlot. The inland, warmer Paso Robles AVA is good for Syrah, Cabernet and Zinfandel. Further south is Santa Barbara County which, despite its southerly location, is one of the coolest viticultural regions in California making it good for Pinot Noir and Chardonnay.
The Central Valley region is comprised of the Sacramento and San Joaquin valleys. This large inland region runs 650km north to south around about 150km inland with the Sierra Nevada range to the east protecting it from the desert like Nevada and the coastal ranges to the west blocking the influence of the Pacific coast. This AVA produces more than half of the state’s grapes, much of it for table grapes and bulk wine production. If you are drinking a wine that is labelled California AVA it is probably from here. It can be divided into the Northern Sacramento River Valley and the larger, hotter San Joaquin Valley in the south. Most premium wines are grown in the Sacramento River Valley but it is the Lodi AVA situated on the boundary of the two valleys that produce some of the best Zinfandel in California. Lodi is 100 miles east of San Francisco Bay and has a unique microclimate due to its proximity to the Sacramento-San Joaquin River Delta. This inland extension of San Francisco Bay allows cool maritime breezes to be pulled inland through to Lodi moderating the temperature enough to make it perfect for high-quality Zinfandel.
The Sierra Foothills region is huge and runs for 260km along foothills of the Sierra Nevada Mountains from Yuba County in the North to Mariposa County in the south. Vineyards were planted here during the gold rush in the mid-1800’s and despite abandonment, during the prohibition years, many of these old, low yielding vineyards are still operation producing high-quality Zinfandel grapes. The high elevation of the region with warm days with cool nights creates an extended ripening period which, combined with rocky, low fertile soils means the area produces concentrated, ripe, red wines made from Zinfandel, Syrah and Barbera.
The South Coast AVA goes from just north of Los Angeles to San Diego. It is a hot dry region so most vineyards are located close to the coast where the ocean breeze helps moderate things or are found in high altitude regions. Wines from the Temecula and Cucamonga AVA's are of the most interest. Rhone Valley varieties such as Syrah, Grenache and Mourvedre do well in both these AVA's alongside Italian varieties such as Barbera and Sangiovese.
Great weather, varied geology due to significant seismic history and closeness to the ocean means California is ideal for grape growing with a wide range of growing conditions making it suitable for many grape varieties and wine styles which are well worth a try.