California carries the winemaking can for the USA because it represents more than 90% of the country's wine output.
Even though the state has 100 American Viticultural Area sub-regions, it's amazing how one region can have so many false generalisations applied to it; like it's chock-full of Merlot or Cabernet Sauvignon, like it only has very cheap or very expensive wine, like it's all about the most famous region of Napa…. The list (amazingly) goes on.
Winding through the county from north to south, the twists and turns in the state's topography and climate are responsible for its variety, making it capable of making anything and everything from cool climate Pinot Noirs and Chardonnays to hot climate, spicy wines from the Syrah grape as well lesser known wines like voluptuous versions of the white grapes from France's Rhône Valley like Marsanne and Roussanne.
South of San Francisco and north of Los Angeles, winemaking regions should be incredibly warm, but in fact they are handily cooled down by ocean breezes. A perfect example of this is in Edna Valley, where the cooler conditions give it the ability to make mineral Chardonnay and peppery Syrah.
We can't talk about California wine without mentioning Zinfandel. Zinfandel is the ultra full-on red grape that's meaty and spicy. Zinfandel red wines are bold, tannic and alcoholic but White Zinfandel is also still very popular, and is the name given to an off-dry to sweet wine that is partially fermented Zinfandel, which means the bottled wine has sugar left in it making it sweeter and less colour, therefore making it a rosé in appearance.
Merlot, as a juicy, plummy and immediately appealing red wine is still hugely popular across California even though it took some bashing after the Californian-based film Sideways, in which Merlot was ridiculed as an inferior grape and Pinot Noir was hailed as the grape of considerable class.