Oak Knoll District (officially the Oak Knoll District of Napa Valley) is an AVA in the southern reaches of California's Napa Valley. Its location near San Pablo Bay means it is one of Napa's cooler AVAs, and is known for its remarkably bordelais red wines made from Cabernet Sauvignon, Cabernet Franc, Merlot and Malbec.
The AVA covers 3360 hectares (8300 acres) of the valley floor immediately north of Napa township and the Carneros AVA. Oak Knoll District borders Yountville and Stags Leap District to the north, and Mount Veeder covers the Mayacamas mountains above.
©Napa Valley Vintners
Like much of the Napa Valley, the Oak Knoll District was first planted to vine during the Californian gold rush of the 1850s, and expanded during the course of the 19th Century. Unfortunately, disease and Prohibition killed off much of Napa's wine industry in the early 20th Century, and it wasn't until the 1960s, when Trefethen Vineyards began to reclaim land in Oak Knoll as vineyard, that winegrowing returned to the area.
Oak Knoll District was declared an AVA in 2004, after the local vinegrowers' drawn-out bureaucratic struggle to gain independent recognition for their terroir. The justification for Oak Knoll District's status as a separate AVA stems from the coolness of the climate. Average summer temperatures are several degrees cooler compared to the likes of St Helena and Calistoga, mostly thanks to the cooling fog and breezes from San Pablo Bay 15 miles (25km) to the south. With a warm spring and a cool summer, the growing season here can span more than eight months and run into October, giving grapes ample time to ripen fully and develop complexity, while not losing critical acidity.
The Bordeaux grape varieties Cabernet Sauvignon, Cabernet Franc, Merlot and Malbec hold sway among Oak Knoll District's red wines. Chardonnay is the pick of the white grapes here, and benefits just as much from the extended growing season as the reds do. Prestigious wineries from outside the AVA now regularly buy in Oak Knoll District fruit for their whites, valuing it for its balance of sugar and acidity, which is rarely found in this part of California.
Oak Knoll District is not to be confused with the longer-established and more prestigious Oakville AVA a short distance to the north, on the far side of Yountville. While Oak Knoll District has made significant progress towards establishing itself on the top tier of Napa AVAs, it still has work to do before gaining the prestige enjoyed by Oakville.