California represents about 90% of total wine grape production in the United States.
edit Facts and figures
California's 900+ wineries produce over 200 million cases per year, with shipments over $5.5 billion, making it the second largest food industry in the state.
edit History
Winemaking in California dates back more than 200 years, when Spanish settlers led by missionaries planted the first grapes along what is now known as Highway 1. The varietal used was Mission grapes, probably originating from Spain. The very first California wine was yielded in 1782 at Mission San Juan Capistrano (mid-way between San Diego and Los Angeles). It was a fortified, sweet wine. After that, vineyards were planed around other California missions, along the coast and inland, as far North as Sonoma. After the Spanish missionary period ended in 1833, winegrowing continued to be centered around the Los Angeles area and Southern California, for most of the century.
Jean-Louis Vignes, a Frenchman from Bordeaux, is credited for introducing fine wine to California and making its wine industry grow to a commercial level. He imported Cabernet Sauvignon vines from Bordeaux and planted them in what is now Los Angeles in the 1830s, and began selling its wines a decade later. By the 1850s another Frenchman, Charles LeFranc, had started planting Cabernet Sauvignon and other varieties in the Santa Clara Valley, using Château Margaux, the finest estate in Bordeaux, as a model. Other pioneering vintners of California followed his initiative and experimented with wines "à la Bordeaux", still around Southern California. In 1857 Count Agoston Harazsthy of Hungary made the first venture North by founding Buena Vista Winery in Sonoma County. Most of California winegrowing regions developed from that time until the end of the 19th century.
The wineries of that area were mostly small-scale, individually owned, and typically tried to mimick the wines being made in Bordeaux, Burgundy and Sauternes. California wineries even named their wines after French appellations such as Hermitage, Bourgogne, Chambertin or Château d'Yquem. However, their wines were of ordinary quality, using whatever grapes they could obtain. Only by the 1910s did vintners start working on choosing the rights soils and climates, and improving their techniques, though most of the winemaking remained small-scale.
As the notion of fine wine began to take shape in the minds of California vintners, a series of disasters struck. Phylloxera appeared in the late 1800s, and wiped out most of California's vineyards in the following decades - 250,000 acres were ruined by 1915. Soon came World War I, then the Prohibition which passed into a Constitutional amendment in 1919. It outlawed the manufacture, transportation, sale and possession of alcoholic beverage from 1920 to 1933, and forced hundreds of California wineries to close permanently. A few wineries kept running, since Californians were still allowed to make wine for their own consumption, or altar wine for the Church.
When the Prohibition was finally repealed, California's wineries were in sad shape, and for the following three decades their wines were plagued by bacterial defects. They were made in vessels contaminated with mold and other microorganisms, which led to undesirable flavors and aromas. Sweet wines were more popular than dry wines, since their defects could be easily masked. Financing for new investments in grapes, vineyards and facilities was hard to find.
At that point, the University of California at Davis played a major role in initiating a much-needed transition, by defining climatic zones for growing fine-wine grapes, identifying five regions rated from coolest to warmest, and establishing strict sanitation guidelines. From the 1940s to the 1960s, Davis researchers greatly helped the wine industry to define and develop the tools they needed to develope a wine market around the country.
In the 1960s, as the wine industry began to stir, consumer tastes developed. Dry wines with varietal names such as Cabernet Sauvignon or Zinfandel became increasingly popular, replacing sweeter wines such as Riesling. White wines were also refined around the 1970s when Sauvignon and Chardonnay started to appear as an alternative to the ordinary white table wine that was being drunk at the time in the US.
The 1970s saw a growing interest in wine from businessmen and professionals who had succeeded in one career but looked for new challenges or something more fulfilling. Owning a vineyard or winery became a status symbol, and many invested heavily in the industry.
In 1976, a Franco-Californian tasting held in Paris to commemorate the US Bicentennial gave the first places to two Napa Valley wineries, in both red and white categories. This victory established a worldwide reputation for California wines, inciting some of the most reknown French winemakers to invest in its vineyards, such as Baron Philippe de Rotschild, owner of the great Mouton-Rotschild estate in Pauillac, who forged a partnership with Robert Mondavi of Napa Valley in 1979.
By the 1990s, earlier assumptions about California wine had vanished, and innovations and refinements continued. An emphasis was put on the French notion of terroir, planting the ripe grapes in the right soil and microclimate. Typically, grapes such as Chardonnay and Pinot Noir were planted in cooler climates, while red varieties such as Cabernet Sauvignon, Merlot and Syrah were planted in warmer areas. The best vineyards were tightly pruned to limit the number of wine clusters; grapevines were trimmed back to expose grapes to direct sunlight early on, so that the grapes would ripen more evenly and fully; and winemarkers started using natural yeasts, and leaving grapes in French oak barrels for long periods, and using minimal filtering, with the intention of making wines as naturally as possible.
Consumer demand for California wine soared in the 1990s, transforming it into a global market, which hasn't stopped growing ever since.
edit Geography and climate

The single greatest influence on California's climate is the Pacific Ocean. Without its cooling effect, most winegrowing areas would be too warm to produce quality wine. Coastal fog and its movement inland in the late afternoon and evening creates a natural air conditioning system, especially during summer months.
Soil is the other major factor. California's soils are young, rich in minerals and fertile. They also vary greatly, which determines the choice of grape to be grown; some will perform better in rich soils and others are better suited for sparse or shallow soils.
The major North Coast valleys, such as Sonoma and Napa, are made of alluvial fans along both sides, which are highly regarded for their rich soil, exposure and drainage.