Wine Academy

California Central Valley

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Shown in yellow on our California wine map, the flat Central Valley stretches more than 450 miles southeast to northwest through the center of the state. The flat, largely irrigated valley is about 40 to 60 miles wide. It features some of the most productive agricultural land on the planet, producing more than half of the fruits, vegetables and nuts grown in the United States. This includes table grapes, raisins and bulk wine grapes, but the climate is too warm for fine wine production. Because of the hot climate, wine grapes with high natural acidity do best, including Chenin Blanc and Colombard. The Central Valley is not an AVA, meaning its wines can only be labeled under the broader “California” appellation.

Sierra Foothills


West of Lodi are the eight counties of the Sierra Foothills AVA. Although well inland, the climate is moderated by the area’s elevation and also by the cooling influence of the Sacramento-San Joaquin River Delta system. This is Gold Rush country. The miners of the mid-19th century were a thirsty bunch. By the 1860s, the foothills had a thriving wine industry, particularly associated with Zinfandel. The gold mania subsided, but the vines continued to grow, in many cases under the loving and expert care of Italian immigrant winemakers. This wine culture, and the toughness of the vine itself, got Zinfandel to the other side of Prohibition. The worst threat to Zinfandel came in the late twentieth century when a new mania—this time for Cabernet Sauvignon, saw Zin vines pulled up and vineyards repurposed. In the nick of time, the thirst for white Zinfandel (which is made from the red Zinfandel grape), allowed Zin to take its place as “California’s native grape.” The AVA’s hundred or so wineries produce Zin, often from old vines (which have no legal definition but are often many generations old), with lesser amounts of Cabernet Sauvignon, Syrah, and even smaller amounts of Chardonnay, Merlot, and Barbera.


Sierra Foothills has five sub-AVAs. The California Shenandoah Valley AVA, El Dorado AVA, Fair Play AVA, and Fiddletown AVA are bunched in the center of the region, in Amador and El Dorado Counties, and focus on Zinfandel. The North Yuba AVA in the northernmost county of Yuba is more removed form the cooling influence of the Delta and has a warmer climate suitable for Cabernet Sauvignon and the Rhône grapes Syrah, Grenache, Viognier and Roussanne.


North Coast AVA.


Six counties make up the North Coast AVA: Marin, Solano, Lake, Mendocino, Napa, and Sonoma. Wines sold under the “North Coast” label are usually blends of grapes from more than one of the counties.


Although Marin County just north of the City of San Francisco is highly affected by urban sprawl, the northern reaches of Marin have extensive agricultural lands that are legally protected from property development. While the entire north coast is known for cool climate viticulture, Marin, sandwiched between the ocean and the bay, may be downright cold. The saving grace is a long growing season. Marin has about 200 acres of grapevines, divided among a handful of family growers, producing Pinot Noir, Chardonnay, Gewürztraminer, and Riesling.


Solano County lies between the eastern reaches of the bay/delta system and the state capital of Sacramento. Two of Solano’s AVAs are part of the North Coast AVA. The Solano County Green Valley AVA, just north of San Pablo Bay, produces Cabernet Sauvignon, Merlot and Syrah on about 800 acres. The Suisun Valley AVA, further north, is one of the state’s oldest wine producing regions, producing a wide range of grapes on over 3,000 vineyard acres.


Lake County directly north of Napa, surrounds Clear Lake, California’s largest lake. Although the county is inland and removed from the influence of the bay and delta system, the lake itself combines with substantial vineyard elevations to prevent the climate from getting too hot. Lake County AVAs include the Clear Lake AVA, the High Valley AVA, and the Red Hills Lake County AVA. The county’s proximity to Napa makes it a prime purchasing source for winemakers from elsewhere, but it also has more than a dozen wineries of its own. Cabernet Sauvignon leads, with Sauvignon Blanc second.


In Mendocino County, on the Pacific Coast directly north of Sonoma, wine grapes are by far the most prominent legal agricultural product, covering 16,862 acres as of 2015: 4500 planted to Chardonnay, 2600 each to Pinot Noir and Cabernet Sauvignon, 1900 to Zinfandel, and 1400 to Merlot. Organic wine grapes account for a total of 3900 acres (and the county has been GMO free since 2004). Mendocino has ten AVAs.

The Anderson Valley AVA is making a reputation for itself in sparkling wines, led by French Champagne house Roederer. The northern end of the valley (one of California’s coolest regions) is closer to the Pacific Ocean than the warmer southern end. Anderson and the nearby Mendocino Ridge AVA produce Pinot Noir and Chardonnay for still and sparkling wines as well as Riesling and Gewürztraminer. A little further north, the Redwood Valley AVA is known for peppery Zinfandels, Potter Valley for Chardonnay, Pinot Noir and Sauvignon Blanc, Eagle Peak for Pinot Noir (from its single winery).


Further north still, the Covello and Dos Rios AVAs total only a few acres of vines between them, producing Cabernet Sauvignon, Cabernet Franc, Chardonnay, Merlot and Zinfandel in warmer inland climates than those appellations further south.


The Yorkville Highlands AVA is a continuation of the southeastward reaching Anderson Valley that at its southern end nudges the northern end of Sonoma’s Alexander Valley. Yorkville Highlands has rocky soil with high gravel content and good drainage. The daytime climate is cooler than Alexander Valley but warmer than Anderson Valley. At night these highlands get chillier than either of their neighbors.


South of Mendocino’s largest city Ukiah (which is not particularly large), the Cole Ranch AVA is the smallest appellation in the United States (only one winery producing Cabernet Sauvignon, Merlot, Pinot Noir and Riesling). In the county’s southeastern corner, the McDowell Valley AVA makes Rhône wines from old-vine Syrah and Grenache. Some of these vines are more than 100 years old. McDowell is also known for dry rosés.

We have saved the two big players, Napa and Sonoma, for last. For starters, let us look at ways in which these neighbors are profoundly different form each other.


  • Sonoma is twice the size of Napa
  • Sonoma has four times the population of Napa
  • Sonoma has a large city, Santa Rosa (population 175,000), while Napa has no large cities.
  • Ocean-facing Sonoma has a cooler climate than inland Napa, although the southern reaches of both counties are also cooled by San Pablo Bay. Some of Sonoma’s ocean fogs do reach eastward across the center of the county to affect Napa.
  • Sonoma has a number of overlapping AVAs, while Napa’s AVAs do not overlap.
  • Sonoma produces agricultural products other than wine grapes (although grapes are number one), while Napa is all grape.

The Mayacamas Mountains physically and climatologically separate Sonoma and Napa. Only two widely separated east-west roads connect the two counties.