Sonoma County: A Primer

Posted on Jul 5, 2017

Sonoma County

Some of the beautiful vineyards at St. Francis winery.

Sonoma County, the “Valley of the Moon”, truly is a bounty of riches: the long valley just 90 minutes north of San Francisco boasts spectacular scenery, a relaxed and laid back vibe, terrific restaurants and is producing top-rated wines from a diversity of micro-climates and grape varieties.

Napa Valley

One of the great Cabernet Sauvignon producers in Napa Valley.

Sonoma is often compared to or contrasted with its neighbour next door: Napa Valley. The two valleys run parallel, separated by the Mayacamas Mountains. Both are terrific tourist destinations and both are among the top wine making regions in the U.S. and, in fact, stand tall among the world’s best wine regions. Napa is the better-known region of the two, but Sonoma has twice the vineyard area and a much greater variety of wines produced. Certainly Cabernet Sauvignon is king in Napa and while other varieties are grown there (notably Chardonnay and Zinfandel) it is Cabernet that carries Napa’s reputation.

Sonoma has a tremendous diversity and perhaps that is why it is less well known. To some extent, Napa equals Cabernet; a pretty simple concept to grasp. But Sonoma equals so many things that it is harder for outsiders to get a good handle on the area. Though Sonoma County is diverse, it is not at all hard to understand. Hopefully this primer will help put you in the right picture.

The first thing that should be made clear when talking about Sonoma is the distinction between Sonoma, Sonoma County and Sonoma Valley. Sonoma is the historic town that sits at the south end of the region. Sonoma County is the large mass of land (1,786 square miles) that has within its borders 17 different American Viticultural Areas (“AVAs”). Sonoma Valley is one of those 17 AVAs, a smaller one located at the southeast end of the county. But nothing to get too fussed about here, as people there use the terms interchangeably.


Iron Horse Vineyards

Sonoma County stretches about 55 miles (87km) north from San Pablo Bay to the town of Cloverdale. It is bordered on the west by the Pacific Ocean and on the east by the Mayacamas Mountains. The Sonoma Mountains separate the rest of the valley from the Pacific Ocean. Despite this separation, the Pacific Ocean has a strong influence on the climates of the various Sonoma AVAs. Cool, damp air and early morning fog come up the valley from San Pablo Bay as well as entering the valley through the Petaluma Gap, a low point in the Sonoma Mountains about a quarter way up the valley. This keeps the valley floor cool and ideal for cool climate viticulture: growing Chardonnay, Pinot Noir and Sauvignon Blanc. The wide temperature swings from cool nights to warm days preserve acidity and complexity in the grapes. Higher up on the hillsides, above the fog line, warmer temperatures are found that fully ripen Cabernet Sauvignon. Zinfandel, Merlot and Syrah also thrive in its varied micro-climates.

The reason Sonoma County has 17 different AVAs is because the climate and soil conditions are simply that diverse. AVA status is granted to wine growing regions that possess unique climate, soils and aspect within their delimited boundary. The Sonoma Coast AVA runs along the Pacific Coast the entire length of the county. It is the largest AVA with 2,000 acres under vine. Created in 1987, it now has within it the newly formed Fort Ross-Seaview AVA, an area of 500 acres given AVA status in 2012. Both AVAs are known for their excellent Chardonnay and Pinot Noir. In the north, the Rockpile AVA produces terrific Zinfandel while the Dry Creek Valley AVA immediately to the south of it does Zinfandel and Sauvignon Blanc. Still in the north, the tiny, one winery Pine Mountain Cloverdale Peak AVA produces Cabernet Sauvignon and Zinfandel while neighbouring AVAs Geyserville, Chalk Hill and Knights Valley also grow Cabernet Franc, Sauvignon Blanc and Chardonnay, and all sit within the larger Northern Sonoma AVA. Further south the Russian River Valley AVA and within its borders the Green Valley AVA are specialists with Pinot Noir and Chardonnay. At the southeastern end of the county is the Sonoma Valley AVA which has within its borders the Bennett Valley, Sonoma Mountain, Moon Mountain and Carneros AVAs.  Pinot Noir and Chardonnay dominate the most southern reaches as they thrive in the cool breezes coming off San Pablo Bay. As you move north those maritime influences are reduced and Merlot, Syrah and Zinfandel are planted. Fountain Grove has just 4 wineries and makes Bordeaux varietals in the eastern part of the valley.

To really get the picture, the always entertaining and super-informative Wine Folly ( has done a tremendous map of the region with all of its AVAs:

Wine Folly

Sonoma County has a tremendous diversity of soil types. In fact, Sonoma County has more different soil types than all of France. There are 259 different soil types that range from loam to volcanic and give distinct characteristics of texture, nutrients and drainage allowing for unique vineyard expressions.

California GrapesDiversity of climate and diversity of soil allows for a wide diversity of grapes that grow well within Sonoma County. In fact over 50 grape varieties are grown in Sonoma County. Chardonnay by far has the largest planting, accounting for over 30% of the total acreage under vine. Next is Cabernet Sauvignon at 16%, Pinot Noir at 14%, and each of Merlot, Zinfandel, Syrah and Sauvignon Blanc are significant. These grapes are grown by over 1,800 different growers.

The 3 mile long Caves

Part of the underground cave at Schramsberg housing their sparkling wine.

With 430 different wineries, diverse micro-climates, diverse soil types and a host of different grapes grown, Sonoma can offer a wine that is likely to please just about everyone’s palate. It is unique in California as the only wine region to produce high quality sparkling wine. Prices for much of Sonoma’s wines remain very fair for the quality level offered. In this regard Sonoma can be distinguished from its neighbor Napa. The vast size of Sonoma County has meant that land prices have not sky-rocketed to the same degree as Napa. It is still possible for Sonoma producers to offer excellent quality without charging huge prices. This is also influenced by a different vibe in Sonoma. Napa has become more attuned to the high-end wine tourist over the years. The tasting rooms along Highway 29 and the Silverado Trail have gone upscale and often charge huge tasting fees and cater to the Mercedes-and-Rolex crowd. Sonoma remains much more dialed back, still very true to its agrarian roots. The top wineries in Sonoma pursue and can achieve the pinnacle of quality, just as much as Napa. But in Sonoma it is done with a little less glitz, and a little more humbleness than some across the mountains. For us, that certainly adds to the charm of the region. Sonoma does have a few “cult” wineries (Marcassin, Peter Michael, and Aubert come to mind), and some can charge very high prices for their top cuvees, but for the most part, most of their wines are very accessible. Personal favourites include:

Talisman Wines

Walter Hansel Winery

Laurel Glen Vineyard

Hidden Ridge Vineyard

Donelan Family Wines

St. Francis Winery

Schramsberg Vineyards

Iron Horse Vineyards

Enkidu Wine

Landmark Vineyards

Hartford Family Winery

Kistler Vineyards

Patz and Hall Winery

Marimar Estate Vineyards & Winery

Ridge Vineyards (Geyserville and Lytton Springs)



    So true your statement “But Sonoma equals so many things that it is harder for outsiders to get a good handle on the area. Though Sonoma County is diverse, it is not at all hard to understand. Hopefully this primer will help put you in the right picture.” That a place thought by many to just be “Sonoma” contains 17 AVAs is pretty remarkable. Most of us count ourselves lucky if we have but one! Particularly like the wines from Ridge Vineyards. Thanks for sharing!

    Post a Reply

    What a brilliant “Primer”! We have visited Sonoma on a couple of occassions and have been wanting to make a return trip. I knew the area was large and diverse, but truly had no idea how much so. 17 AVAs, 269 soil types and 430 Wineries leaves quite a bit of exploring to do! For those of us who like to explore lesser known varieties and smaller wineries, do you have a suggestion of an AVA or area to start with?

    Post a Reply
    • Hi Robin, we’ve been visiting for many years and STILL haven’t reached them all! As for which one to start with, depends on your preference for AVAs – Definitely Russian River Valley, Chalk Hill & Sonoma Valley. Definitely reach out when you’re going and we’re happy to make some specific winery recommendations!

      Post a Reply

Leave a Reply

Share This