Even before California joined the United States, colonists had discovered that the area had good potential for wine making. Adequate rain, lots of sunshine, and plenty of warmth ; these were just the conditions prevailing in the best wine-growing areas of Spain and most of Mediterranean Europe. There was no reason why California could not produce wines to match the best and finest of wines produced in the Old Continent.
   For a long time, however, it did not. Until the 1960s, California wines were not all that well-known even in the USA! Wine coming out of California tended to be ordinary-quality  table wine, nothing more.  Then some enterprising wine producers decided that they ought to be able to do much better than that, and since then California wine production has developed massively in volume and,  in many areas, in quality too.

  Nowadays California's vineyards are divided into five areas. The North Coast area, including Mendocino, Sonoma and the Napa Valley is the area that produces many of the most prestigious wines.  The Sierra foothills is an area that produces similar wines.  Two central wine growing areas are the Inland Valleys area, covering the Central Valley areas of California, and the Central Coast area extending from the Bay Area down to Santa Barbara. With its large fertile spaces, the Central Valley is the Languedoc or la Mancha of California wine production, producing some three quarters of all the wine produced in the state.  In the south lie the smaller vineyards of Southern California, best known for their Proven�al and Italian-style wines.
. The most prestigious wine producing areas in California are found to the North Coast vineyard area, in the Sonoma and Napa Valley AVAs. AVA's are designated "American Viticultural Areas", a geographic label corresponding to AOP (Appellation d'Origine Prot�g�e, formerly App�llation contr�l�e) in France, or Denominaci�n de Origen in Spain.
  With their balance between warm sunshine and cooler periods, when the winds blow in off the Pacific Ocean, California's coastal areas are eminently suitable for production of wine from the grape varieties used in France, notably Pinot Noir, Cabernet-Sauvignon and Chardonnay.  
  Vineyards in areas south of San Francisco tend to be more into volume production, which does not mean they do not also produce some very good wines. With regard to mass market wines, the larger wine producers in southern California were leaders in the modern tradition of producing branded wines with constant quality, unlike the more individual top-of-the-range wines from smaller vineyards, which tend to very in quality from year to year.
  The biggest California wine producer, and the world's biggest privately-owned wine producer, is Gallo, based in Modesto, in the San Joaquin Valley.
  A classic example of California wine branding and blending technique is Meomi wine, blended from wines produced in the Sonoma, Monterey and Santa Barbara viticultural areas.  The result is a standard quality wine that, according to the producers, is "full-flavored, opulent yet exceptionally smooth."

California winery visits 

A visit to the winery, and the opportunity to taste wines straight from the cellar, is part and parcel of any wine tourism; and naturally there are large numbers of California wineries that welcome visitors for wine tasting and cellar visits, specially in the wine growing areas to the north of San Francisco. While wineries can be visited in all California wine growing areas, it is the areas of Napa Valley and Sonoma that are most renowned for their winery visits.
  One of the most popular wineries to visit is  Castello Di Amorosa, the V.Sattui vineyard at St. Helena, in the Napa Valley.... and no wonder! This must be the only full reproduction in the USA of a 13th century Italian castle! The winery is open 7/7, and reservations are not needed.  Website
  A less well-known Napa Valley winery is the Hess Winery, a historic winery dating from the late 19th century, that includes a museum. Hess was one of the first California wineries to develop sustainable winegrowing practices. Website
  For the best California Burgundies, a reputed winery is the Peay Vineyard, in Cloverdale, just off Highway 101 in the Sonoma wine growing area. Specialising in French grape varieties, Pinot noir, Syrah and Chardonnay, this however is a small vineyard, and visits are by appointment except on the occasional open days. Website
  A bigger Burgundy-style vineyard, offering visits and wine tasting, is the  Chateau Montelena vineyard at Calistoga, in the Napa Valley. This winery is known for its stone ch�teau built in 1888, originally a wine-ageing facility. Ch�teau Montelana uses organic farming methods to produce small volumes of top-quality wine, in particular Cabernet-Sauvignon reds and Sauvignon whites. Website