California's North Coast AVA is vast, covering more than 3 million acres (1.2 million ha) of land to the north of San Francisco. Its large size should not be taken as an indicator of low quality or a lack of regional identity, however – the area is home to some of the wine world's most valuable and distinctive real estate. The Napa Valley, Sonoma Valley, Russian River, Stags Leap and Carneros districts – the aristocracy of American wine – are all located here in the North Coast.
The large number of respected AVAs located within the North Coast means that high-quality wines from the area are typically labeled not as 'North Coast' but with the titles of these more prestigious, location-specific areas. Most wines bearing the 'North Coast' AVA title are mass-produced blends made from grapes harvested in several of the AVA's regions.
A long, rough-edged rectangle, the North Coast AVA measures 120 miles (195km) from north to south, and about half that from east to west. Other wine regions of this scale are usually delimited using political or administrative boundaries such as county, state or national borders, which have no intrinsic relevance to wine production. Impressively, this is not the case here. The North Coast AVA boundaries are defined almost entirely by topography, hydrography and other geographical factors, all of which do, ultimately, have their influence on wine quality.
Despite the above, the name 'North Coast' must be taken in context. Although some parts of the AVA lie several hundred meters above sea-level, and more than 50 miles (80km) from the nearest beach, the name usefully distinguishes the area from the much hotter, drier inland areas: the Central Valley and Sierra Foothills.
It is impossible to give a concise, cover-all description of geology and climate for such a large area, but there are a few generalizations true of all North Coast vineyards. As can be expected in a mountainous region close to the coast of a vast ocean, summer temperatures here are significantly lower (and winters noticeably milder) than those experienced further inland. Cooling coastal breezes, refreshing fog and crisp mountain air are all key ingredients of the North Coast terroir. Each of these helps in some way to balance out the one constant that affects all vineyards here: warm, bright California sunshine.
The grape varieties grown around the North Coast are the same as those grown all over California as a whole. The obvious king and queen here are Cabernet Sauvignon and Chardonnay, which together make up roughly half of all plantings. Other significant varieties include Zinfandel (in warmer areas) Pinot Noir (in cooler areas), Merlot and Sauvignon Blanc.