90% of the wine produced in the USA comes from California, which itself is the 4th largest producer of wine in the world. Another great reason to visit the Golden State!
The Wine Country regions are easily accessible from San Francisco either by car, or you might prefer to take a ferry and private coach to join the Napa Valley Wine Train. This promises a leisurely 3-hour journey aboard immaculately restored vintage rail cars as you sample both culinary delights and the local wines.
Wine tasting in California is less formal than many parts of the world and one of the reasons why wine tasting "virgins" like to visit this region. Here there is a casual, friendly, "hey, come in and sample with us" approach to the whole experience. Add to this the fact that the area as a whole is stunningly beautiful and includes some of the best restaurants in the whole of the state.