San Francisco Bay is a multi-county American Viticultural Area (AVA) which is centered and surrounds the San Francisco Bay Area of Northern California. It was established as the nation's 135th and the state's 81st appellation on January 19, 1999 by the Bureau of Alcohol, Tobacco and Firearms (ATF), Treasury after evaluating the petition submitted by a consortium of nearly 75 growers and vintners led by Wente Brothers proposing the viticultural area known as "San Francisco Bay."
It lies within the larger Central Coast viticultural area and includes San Francisco and counties encompassing the areas known as "South" and "East Bay." This consists of Alameda, Contra Costa, Santa Clara, and San Mateo as well as portions of Santa Cruz and San Benito Counties. "North Bay" counties of Sonoma, Napa and Marin were excluded for they reside within the North Coast viticultural area with its distinct properties. ATF also concluded the established Santa Cruz Mountains viticultural area exhibits features and characteristics unique to its boundaries when compared to the surrounding areas, therefore, it was excluded from the "San Francisco Bay" viticultural area.
"San Francisco Bay" AVA expands and encompasses six designated AVAs within its boundaries: Livermore Valley, Santa Clara Valley, Lamorinda, Santa Cruz Mountains, Ben Lomond Mountain and most recent Contra Costa. In conjunction with establishing "San Francisco Bay" viticultural area, ATF amended the boundaries of the Central Coast viticultural area to include San Francisco Bay entirely as the previous boundaries of Central Coast encompassed only smaller portions of the San Francisco Bay region. Approximately was added to Central Coast with an additional under vine. In 2006, the Alcohol and Tobacco Tax and Trade Bureau {TTB} added to San Francisco Bay viticultural area and the Central Coast viticultural area to conform to the expanded boundaries of the Livermore Valley viticultural area.
History The city of San Francisco became an important port during the 1850s, when the California gold rush in the Sierra Nevada mountains brought a huge influx of European and Chinese immigrants, in search of fortune. It was around this time that European grape varieties began to be planted throughout the Santa Clara Valley, Contra Costa County and other California regions to supply the demand of the thirsty population. The city was filled with winemakers, brokers and wine warehouses; the 1893 city directory included more than 120 entries under "native wines." Gundlach-Bundschu's block-long winery was destroyed in the 1906 San Francisco earthquake. Geyser Peak had a Montgomery St. facility and legendary vintner Louis Petri got his start moving barrels in his family's San Francisco warehouse. But by the 1970s, Napa and Sonoma wineries were coming of age and the wine lifestyle had shifted away from "The City."
The watershed event in the viticulture industry occurred in 1976 during the United States Bicentennial celebration. British wine connoisseur, merchant and founder of France's first private wine school, L'Academie du Vin, Steven Spurrier, organized the Paris Wine Tasting of 1976 where renown French oenophiles participated in a blind tasting to judge the best wines from California's wine regions and France's prestigious Bordeaux and Burgundy regions. George Taber, the sole journalist who attended the event, penned the article "Judgment of Paris" in Time magazine reporting the shocking results when the local judges ranked the California vintages, from Napa and Monterey, higher than the primer French labels in both Chardonnay (white) and Cabernet Sauvignon (red) categories.
Naming "San Francisco Bay" is a locally, nationally and internationally recognized place name. ATF concluded that "San Francisco Bay" is the appropriate name for the area. San Francisco Bay is widely recognized as the well-known body of water by that name and, by inference, the land areas that surround it. Within the grape growing and winemaking community, the name San Francisco Bay has always been identified with the "San Francisco Bay" viticultural area.
The counties of San Francisco, Contra Costa, Alameda, Santa Clara and San Mateo—within which the area is located—border the San Francisco Bay. Santa Cruz County, although it has no Bay shoreline, has traditionally been associated with the place name "San Francisco Bay." Also included is the portion of the Santa Clara Valley located in San Benito County. The names "San Francisco Bay Area" or "San Francisco Bay region" sometimes refer to an area that is different than the area discussed in the petition. Although sources differ in how broadly they define the San Francisco Bay region, the various definitions, without exception, include the counties mentioned above. The following sources were cited by the petitioner as being representative of the consensus among experts that the petitioned area is widely known by the name San Francisco Bay. The name "San Francisco Bay" is more frequently and more strongly associated with the counties lying south and east of the San Francisco Bay than with nearby counties to the north. For example, the 1967 Time-Life book entitled "The Pacific States", describes the San Francisco Bay Area as a megalopolis with the city, of San Francisco, as the center, stretching south to San Jose and from the Pacific to Oakland and beyond. The weather expert Harold Gilliam, in his book "Weather of the San Francisco Bay Region", discusses an area including San Francisco, San Mateo, Alameda, Contra Costa, and Santa Cruz Counties. James E. Vance Jr., Professor of Geography at the University of California, Berkeley, studied the same area in his book entitled "Geography and Urban Evolution in the San Francisco Bay Area". Also, climatologist Clyde Patton studied the same region in his definitive work "Climatology of Summer Fogs in the San Francisco Bay Area". Mr. Vance's and Mr. Patton's maps of "Bay Area Place Names" were included with the petition. A final source is Lawrence Kinnaird, University of California Professor of History, who wrote a "History of the Greater San Francisco Bay Region". Mr. Kinnaird's book also covers the counties of San Francisco, Santa Clara, Alameda, Contra Costa, San Mateo, and Santa Cruz.
Terroir
Topography San Francisco Bay AVA is distinguished by a marine climate which is heavily influenced by the proximity of the San Francisco Bay and the Pacific Ocean. Specifically, the San Francisco Bay and local geographical features surrounding it permit the cooling influence of the Pacific Ocean to reach farther into the interior of California in the Bay Area vicinity than elsewhere along the California coast. The waters of the San Francisco Bay as well as urban areas, particularly the City of San Francisco, were purposely included since San Francisco Bay is the source of the viticultural area's weather and the focal point of its history. Although it is not a likely vineyard site, the city has long been a wine industry hub.
The weather in the Bay region is a product of the modification of the onshore marine air masses by the topography of the Coast Ranges, a double chain of mountains running north-northwest to south-southeast. Each chain divides into two or more smaller chains, creating a patchwork of valleys. The elevation of the western chain of the coastal ridge is generally higher than the altitude of the inversion base, the inversion acts as a lid to prevent the cool onshore flowing marine air and fog from rising over the mountains and flowing inland. Because of this, successive inland valleys generally have less of a damp, seacoast climate and more of a dry, continental climate. This pattern is modified by a few gaps and passes in the mountain ranges that allow marine influences to spread farther inland without obstruction. These inland areas are, however, somewhat protected from the Pacific fogs, which are evaporated as the flow is warmed by passage over the warmer land surfaces.
The three largest sea level gaps in the central California coastal mountainous barrier are (north to south): Estero Lowland in Sonoma, Golden Gate into San Francisco Bay, and Monterey Bay. Several smaller mountain pass gaps (San Bruno and Crystal Springs) sometimes also allow for the inland spread of coastal climate in the Bay Area when the elevated inversion base is high enough.
The Bay Area climate is greatly modified by San Francisco Bay, whose influence is similar to that of the ocean, i.e., it cools summer high temperatures and warms winter low temperatures. The narrowness of the Golden Gate limits the exchange of bay and ocean waters, and thus Bay waters are not quite as cold as the coastal ocean currents during the summer. Marine air exits the San Francisco Bay (without having experienced the normal drying and heating effects associated with over-land travel) in several directions. The predominant outflow is carried by the onshore northwesterly winds toward the south through the Santa Clara Valley to Morgan Hill and to the east via the Hayward Pass and Niles Canyon. Temperatures at given locations in the Bay Area are thus dependent on streamline distance (actual distance traveled) from the ocean, rather than its "as the crow flies" distance from the ocean.
Livermore Valley temperatures show this phenomenon. Ocean air flows across San Francisco Bay, through the Hayward Pass and Niles Canyon, and into the Livermore Valley, causing a cooling effect in summer and a warming effect in winter. In summary, because of the interaction of topography with the prevailing winds in the Bay Area, the Pacific Ocean and San Francisco Bay are the major climatic influences in the "San Francisco Bay" viticultural area. This interaction has two principal effects: (1) to allow the coastal influence of the Pacific Ocean to extend farther east than otherwise possible, and (2) to modify that coastal influence because of the moderating effects of Bay waters on surrounding weather.
Climate Coastal influence The unifying and distinguishing feature of the "San Francisco Bay" viticultural area is the coastal influence of both the Pacific Ocean and the San Francisco Bay. Coastal areas north of the appellation area are influenced by the Pacific Ocean and by weather in the area is the Pacific high pressure system, centered a thousand miles off the Pacific Coast. During winter months, its location south of San Francisco allows the passage of westward moving, rain producing, low pressure storms through the area. During the summer months the high is located closer to the latitude of San Francisco. It then deflects rain, producing storms to the north and a dry summer climate in the San Francisco area.
The winds from the high (which flow onshore from the northwest to the southeast) produce a cold southward flowing surface water current, called the "California Current", off the California coast by a process called "upwelling", in which cold deep water is brought to the surface. When moist marine air from the Pacific High flows onshore over this cold water, it cools, producing fog and/or stratus cloud areas which are transported inland by wind.
Meteorology