Geological History

The San Francisco Bay AVA territory has had great historical significance with respect to wine, but also to California and the United States overall. The Santa Clara Valley AVA and Livermore Valley AVA are covered individually and in detail elsewhere on this site. The text in this section will focus on formation of the San Francisco Bay and then viticultural history outside those two nested regions. 

The San Francisco Bay is vast, but very young in geological terms. To a large extent, the landforms and soils of the Bay Area are as well. One million years ago, many millions of years after Napa Valley’s Vaca and Mayacamas mountains began to form, the Bay Area was much larger than it is today. But, there was no bay in the area. 

The coastline extended more than 25 miles (40 km) further west, because an ice age meant sea levels were lower. Today’s Farallon islands were mountain peaks on dry land. And the inland mountains contained a vast lake, Corcoran, in what is now the Central Valley, referred to as Inland Valleys in these guides. 

Then, about 560,000 years ago, a continuing westward movement of the Pacific Plate caused elevation changes. The southern end of Lake Corcoran rose up and emptied the lake in torrents that scoured the land as the water rushed toward the ocean. The force of that water created channels and basins that would later fill with water. 

Roughly 10,000 years ago, the earth’s last Ice Age ended. Sea levels rose as the ice melted. And, again, water rushing from inland scoured the earth, moving and depositing boulders and soil, as it went. The bay was initially fairly dry. But, a continued rise in sea levels, along with water flowing down from the Sierras, eventually filled it, even beyond the level it is today. Over the centuries since, the bay’s level has risen and fallen, creating new layers of sedimentary soil.

The Bay Area’s first citizens probably arrived about 6,000 years ago. When the Spanish arrived in 1769, the Ohlone were the area’s primary tribe.

Within just a few decades, their population was devastated. Some 60,000 died from a variety of causes. By the mid-nineteenth century, fewer than 1,000 still lived in the area. They were essentially extinct well before the beginning of the twentieth century. 

The Spanish Missions certainly gave viticulture its start in the Bay Area. However, their vines were much less important than the missions’ roles in beginning settlements and routes of travel. The Spanish, and then Mexican, governments made grants of land to various people, giving them vast tracts with the assurance that it would be tamed, farmed, ranched, and settled. 

The acreage of individual grants was high, so farming and ranching them was a significant, commercial enterprise. Many different crops would be planted, winegrapes often among them. The practice of commercial winemaking was accelerated when the United States took possession of California without breaking the granted tracts.

Equally important was the 1849 California Gold Rush.

The population would increase greatly. In some cases, it literally did so overnight. There were so many people coming into the area by sea, that the large sailing ships they abandoned in the bay might be used as warehouses or businesses. In the end, most were either scuttled, sinking to the bottom of the bay, or covered with earth to become part of the San Francisco land mass. 

The influx of people, mostly men, meant huge demand for necessities. That included liquor and wine. So, demand for wine grew rapidly. And, with the emergence of San Francisco and Oakland as significant ports, they were well positioned to serve other markets. The phylloxera crisis in Europe meant a huge, unmet demand for wine there. Wine from the North Coast and the Bay Area sailed out of the bay to help slake that thirst. 

The gold rush waned, but the influx of immigrants did not. They came to California, either across the continent by railroad or into the bay by sea, in search of economic opportunity or to escape continental wars. Immigrants from Italy, France, and Germany were particularly important in ramping up wine production in the Bay Area and California overall.

Beyond the Livermore and Santa Clara Valleys, one of the most important growing areas was in eastern Contra Costa County. That area, in the general vicinity of the town of Oakley, saw significant plantings in the 1890s. That’s just a few years after Livermore’s first wineries were established.

Some of the very same vines planted then continue to make great wine today. The deep, sandy soil is both resistant to phylloxera and excellent for growing Zinfandel. And, since Zinfandel is a variety whose vines can thrive for more than a century, the area is home to some of California’s best, and most historic vineyards. Contra Costa County has more Zinfandel and Mourvèdre—which is also long-lived—than any other county in the San Francisco Bay AVA.

While San Francisco may be too cold and foggy during the growing season to be a good viticultural zone, not to mention its small size and consequent lack of space for agriculture, it has been a major wine producer. Grapes would arrive by boat from the East Bay, Napa Valley, and Sonoma to be turned into wine. There was a lot of local demand, but wines produced and bottled in San Francisco were sold across the United States and in Europe as well.

The wine business was badly hurt by the 1906 earthquake and fires.

Having been stored in enormous brick tanks and cisterns that ruptured with the tremors, wine briefly turned some streets into intoxicating rivers. One wine source alone, the California Wine Association (CWA), a dominant syndicate of seven big wine merchants, saw 215,000 bottles burned and tanks holding 4,750,000 gallons (17,981,000 liters) destroyed.

When the CWA rebuilt, it did so across the bay in Richmond, Alameda County. The new 47-acre (19 ha), waterfront wine production and storage facility was dubbed “Winehaven.” While it lasted, it was the largest winery in the world, its capacity 12 million gallons (45 million liters) by 1910.

But it lasted just a decade. Prohibition put the CWA out of business and made Winehaven obsolete. Of course, Prohibition devastated most of California’s wine business. Some Bay Area producers, such as Concannon and Wente, survived by selling grapes or making wine for sacramental purposes. Most vineyards, however, were torn out, to make way for crops that could be legally sold.

Acreage did decline in the early 20th century, largely due to Prohibition. It’s still declining today, because of urban encroachment.

But, at the same time, focus on the area’s vineyards is increasing and wineries committed to their preservation are buying vineyards when possible. Now, the Bay Area’s urban winemaking tradition is being revitalized. There are numerous producers in San Francisco, Oakland, on the island of Alameda, and even under the Bay Bridge on Treasure Island. These make wine from San Francisco Bay AVA fruit, but also from grapes sourced elsewhere. Climate-controlled trucks make it possible to receive grapes in great condition from hundreds of miles away.

Sir Francis Drake lands in the Bay Area and claims it for England, but England didn’t return

Spanish explorers arrive

Spain establishes the Presidio and Mission San Francisco de Asis in present-day San Francisco

Franciscan friars establish Mission Santa Clara de Asis

El Pueblo de San José de Guadalupe established

Mission San José established, the fourteenth of California’s 21 Spanish missions

Mexico assumes control of Spanish lands in California

Robert Livermore plants the first vines in Livermore Valley

United States military captures settlement of Yerba Buena

Lt. William A. Bartlett, alcalde (Spanish title for a municipal magistrate) of Yerba Buena, renames it San Francisco

California ceded to the United States by Mexico

Population of San Francisco increases 25x due to gold rush

California granted statehood; San Jose designated its capital

Town of Oakland incorporated

Santa Clara Valley wineries win awards in California competitions

Central Pacific Railroad builds Oakland Long Wharf, facilitating sea trade

The University of California, Berkeley, founded

Governor Leland Stanford buys Warm Springs Ranch (and vineyard)

Charles Wetmore founds Cresta Blanca Winery in Livermore Valley

Carl H. Wente and James Concannon found their wineries in Livermore Valley

Charles Wetmore’s Cresta Blanca is first American winery to win top prize at an international competition

Duarte, Evangelho, and Mazzoni-Live Oak vineyards all planted in what is now Oakley, in eastern Contra Costa County

Earthquake and subsequent fires destroy much of San Francisco

Prohibition begins

Precursor of the Tri-Valley Conservancy established to protect viticulture in Livermore Valley and neighboring areas from urban sprawl

Livermore Valley AVA established

Pacheco Pass AVA established

Santa Clara Valley AVA established

San Ysidro AVA established

San Francisco Bay AVA established

San Francisco Bay AVA expanded to include 88 acres in Solano County

Lamorinda AVA approved