San Luis Obispo County, on California’s Central Coast, has one of the longest winegrowing histories in North America, with vineyards planted by Spanish missionaries over 200 years ago. It has four distinct AVAs (Arroyo Grande, Edna Valley, Paso Robles and York Mountain) each with its own terroir. A maritime influence affects the southern AVAs, as their east-west valleys allow cool Pacific breezes and coastal fog to enter unencumbered. Towards the north, York Mountain has just one winery, the longest continuously operated winery in the county. The largest and warmest AVA is Paso Robles, which is protected from much of the coastal influence by the Santa Lucia Mountains. After a long dormancy, modern commercial viticulture began in the early 1970s, with plantings of vineyards in the Edna Valley by the Chamisal and Paragon vineyards, both trying to produce Burgundy-like Chardonnay. Acreage of vine has increased almost four fold since 1990, with close to 25,000 acres currently under vine. Of all these AVAs, Paso Robles is gaining the most attention, with structured Cabernet Sauvignon and Rhone varietals, produced by a dynamic group of young winemakers.