Napa Valley AVA is the most famous winemaking region in the United States and one of the most prestigious in the world. With nearly 43000 acres of vineyards and more than 300 wineries it is the heart of fine wine production in the United States. Winemaking started in Napa in 1838 when George C. Yount planted grapes and began producing wine commercially. Other winemaking pioneers followed in the late 19th century including the founders of Charles Krug Schramsberg Inglenook and Beaulieu Vineyards. An infestation of phylloxera an insect that attacks vine roots and the onset of Prohibition nearly wiped out the nascent Napa wine industry in the early 20th century. But by the late 1950s and early 1960s Robert Mondavi and other visionaries were producing quality wines easily distinguishable from the mass-produced jug wines made in Californias Central Valley. Napa Valleys AVA was established in 1983 and today there are 16 sub-appellations within the Napa Valley AVA. Many grapes grow well in Napas Mediterranean climate but the region is best known for Cabernet Sauvignon. Chardonnay is also very successfully cultivated and about 30% of the AVAs acreage is planted to white grapes with the majority of those grapes being Chardonnay