Wine Institute Articles on Northern California Viticultural Areas
The North Coast American Viticultural Area (AVA) in California, covers more than three million acres, includes Napa, Sonoma, Mendocino and Lake counties, and portions of Marin and Solano counties.
The area forms a slightly crooked rectangle, approximately 100 miles long and more than 50 miles wide. A winemaking mecca since the mid 19th century, today the area features roughly 730 wineries, roughly half of the total wineries in the state.
American Viticultural Areas are to appellations of origin like grapes are to fruit. AVAs are delimited grapegrowing areas distinguishable by geographic, climatic and historic features, and the boundaries have been delineated in a petition filed and accepted by the federal government. In size, AVAs range from extremely small to extremely large. AVAs are one kind of appellation, but not all appellations are AVAs. An appellation can also be a political designation, such as the name of a country, the name of a state or states, the name of a county or counties within a state. More information on AVAs and appellations can be found on the Wine Institute website at http://www.wineinstitute.org/ava/index.html.
NAPA VALLEY
Established in 1981, the Napa Valley AVA covers 225,300 acres of land, encompassing almost the entire county of Napa and is home to 391 brick and mortar wineries. Within that area, there are 44,000 acres of vineyards planted. Cabernet Sauvignon is king in Napa Valley with a total of 17,300 acres, and Chardonnay is the most widely planted white wine variety with 7,600 acres. Napa crushed about 120,000 tons in 2004 or four percent of the wine tonnage for California.
The Napa Valley is bordered by two mountain ranges the Vaca on the east and the Mayacamas, rising well above 2,000 feet and bordering the adjacent Sonoma County, on the west. Mt. St. Helena (4,343) stands sentry at the northern end of the appellation where the valley ends at the town of Calistoga. This is the warmest locale in the region. About 30 miles away near the city of Napa, the southern end of the valley opens to San Pablo Bay, an interconnecting arm of the San Francisco Bay system.
A uniquely diverse winegrowing appellation, the Napa Valley formed much like the rest of the North Coast through a geological evolution active with colliding tectonic plates (large pieces of the earth's crust), volcanic activity and changes in sea level as water alternately advanced and retreated over the southern end of the valley several times. As a result of these geological events that took place over a 60-million-year history, the Napa Valley has soils of volcanic, maritime and alluvial origin, with more than 30 different types identified.
Defined by mountain ranges and a proximity to the Pacific Ocean, the Napa Valley enjoys a temperate climate with a long growing season of sunny, warm days followed by cool evenings. Within the Napa Valley AVA, there are 14 other AVAs with distinct microclimates and terrains formed by a varied topographical configuration of hills, exposures and elevations. The Napa Valley AVA is also part of the North Coast AVA.
SONOMA COUNTY
The appellation of Sonoma County totals more than one million acres of land of which 60,000 acres area planted to winegrapes. The county includes 13 distinct AVAs as well as being a part of the North Coast AVA. The larger Sonoma Coast AVA has with 517,000 acres. Chardonnay takes the lead as the most planted variety with 15,400 acres, and Cabernet Sauvignon is the next most planted variety with 11,800 acres. The area crushed about 166,000 tons or about six percent of California's total wine type tonnage in 2004.
Sonoma County is 52 miles wide and 47 miles long and is currently home to 260 wineries. On the east, Sonoma County borders Napa Valley along the Mayacamas Range. About two million years ago, volcanic eruptions deposited a series of ash and lava called the Sonoma Volcanics throughout much of Sonoma and Napa Counties, especially along the Mayacamas Range. The western edge of the County is the California coastline along the Pacific Ocean. Sonoma County borders Mendocino County in the north and Marin County in the south.
Luther Burbank called Sonoma County the chosen spot of all the earth as far as nature is concerned. A vastly diverse range of topography, including numerous small valleys with distinct microclimates, the Russian River and the Pacific Ocean, all characterize the region. A moderate climate with a cooling maritime influence, Sonoma County embodies ideal and diverse grapegrowing weather: from valley to hillside, moist ocean coast to dry inland, and cool southern regions that complement the warmer, more northern areas.
MENDOCINO COUNTY
Mendocino is an approved American Viticultural Area with 275,200 acres. The total area planted to vineyards is 15,500 acres. About 4,400 acres are planted to Chardonnay, 1,900 acres to Pinot Noir, and 2,500 acres to Cabernet Sauvignon. Approximately 25 percent of the total vineyard acreage in Mendocino County is certified organic. Of the 10 distinct winegrowing regions within Mendocino County, eight are official American Viticultural Areas, and the remaining two are proposed viticultural areas. There are 56 wineries and over 250 growers harvesting approximately 56,000 winegrape tons, representing about two percent of the state's wine tonnage.
Located directly north of Sonoma County and about 90 miles north of San Francisco, the Mendocino wine region is bounded by California's Coastal Mountain Range, the Pacific Ocean and the great northern redwood forests. A mountainous region, it is part of the seismically active Coast Range and is also the place where the San Andreas Fault reaches the ocean. Almost 60 percent of the county is blanketed with coniferous forests. Most of the vineyards are located in the inland valleys in the south and east areas of the region. The vineyards growing white wine grape varieties are located on flood plains and alluvium along the Navarro and Russian Rivers. Most of the red varieties are grown on the bench lands above.
LAKE COUNTY
The western portion of Lake County comprises the North Coast AVA. It encompasses the Clear Lake AVA, which in itself has 168,900 acres of land. Within Lake County, a total of 8,260 acres are planted to winegrapes. This is expected to double in the next few years, as many new vineyards are being planted. Cabernet Sauvignon is the most planted variety with 3,300 acres. Sauvignon Blanc is the second with 1,770 acres. Fourteen wineries are located in the region. About 20 out-of-county wineries purchase Lake County grapes from independent growers. Lake County crushed 28,000 tons in 2004, about one percent of California's total wine type tonnage.
Lake County surrounds Clear Lake, the largest natural lake in California. The vineyards are planted throughout the county, from the agriculturally rich valley at 1,370 feet elevation (lake level), to the rocky red volcanic soil at more than 2,000 feet elevation around Mt. Konocti, a dormant volcano in the Pacific Rim chain. These elevations provide cooler winter conditions and a later start to the growing season. Summer growing conditions are suitably warm to ripen the grapes and the elevation allows rapid cooling in the evening. Few grape pests can tolerate the altitude and cool climate. Lake County growers are committed to sustainable farming and participate in year long educational programs to this end.
MARIN & SOLANO COUNTIES
Marin County has 87 acres of vineyards and 13 wineries. Bordered on three sides by the cooling influence of the Pacific Ocean and San Francisco Bay, the area grows mostly the early maturing Pinot Noir and some Chardonnay. The northeastern half of Marin is officially in the North Coast AVA. A small portion of Solano County, forming the southeast tip of the North Coast AVA, has three AVAs, covering an area of more than 21,200 acres. It too receives the cool maritime influence with ocean breezes flowing through the San Francisco Bay and the Delta.
The vineyards and wines of California's North Coast are recognized worldwide for their quality and diversity. There is a sense of place that identifies the region as well as the people. From the days of the Gold Rush of 1849, this part of the state has embodied the pioneering spirit and innovation that still energizes the California wine business.
Article prepared by the Wine Institute October 10, 2005