This large viticultural area encompasses one-hundred-and-forty-thousand hectares and includes notable sub-appellations such as the Russian River Valley, Chalk Hill and Knights Valley, as well as the eastern portion of the Sonoma Coast AVA. It was established in 1990 largely to deal with the issue of wineries wishing to apply the words ‘estate bottled’ to their label. Under current regulations this was only permitted if grapes were grown and vinified in a single AVA and hence, large producers with vineyards in multiple appellations were potentially prohibited from using the phrase. Amongst those most vehemently in favour of the new appellation was the Californian wine giant, E. & J. Gallo who like many others stood to benefit from its designation.
Owing to the diverse topography and geology, as well as the sheer size of the Northern Sonoma AVA, a number of different microclimates exist within its bounds. At the appellation’s southern borders, the influence of the ocean is still felt strongly with the fog and marine air from San Pablo Bay creating a cooler climate suitable for Chardonnay and Pinot Noir. However, the northern portion of the appellation feels limited impact from the ocean and is subsequently much warmer; Bordeaux varieties Cabernet Sauvignon and Merlot are more successful here, and in the hottest pockets - particularly in Dry Creek Valley, the emblematic Zinfandel also thrives.
There are numerous wineries across the Northern Sonoma wine region producing premium varietals for the domestic and international market. Where the entire process from vine to wine takes place within one of the designated sub-appellations, it is usual for the bottles to display the name of the more specific and arguably more prestigious AVA. However, quality wines made from grapes grown across multiple AVAs continue to be made under the Northern Sonoma umbrella.