The Western front

Head north out of San Francisco, over the Golden Gate bridge, and Route 101 delivers you in Sonoma County. It's one of California's larger coastal counties and one of its most historic. OK, so it may not have as many chichi restaurants and Architectural Digest homes as its flashy neighbour, Napa, but it has charm aplenty and is refreshingly down-to-earth. And there are vineyards everywhere.

Sonoma has been growing grapes since the middle of the 19th century on some pretty diverse soil types. The climate is a little more homogeneous. Vintages vary from pretty good to, well, really good, so your average Californian wine drinker isn't greatly bothered about vintage variation. He is bothered about vineyard site, though. Complexity of appellation is the name of the game here and Sonoma has plenty of those.

The region has divided itself into 12 American Viticultural Areas (AVAs) and sub-AVAs. If you took France and turned it upside down, you'd have Sonoma - with Pinot Noir and Champagne in the south and chunky reds in the north. Among them there's Alexander Valley, the largest and most planted of Sonoma's vineyard valleys, extending from the Pinot Noir-loving Russian River (another Sonoma AVA) to the Mendocino county line in the north.

There's Chalk Hill, a tiny sub-AVA of the Russian River Valley; Dry Creek - otherwise known as "the Zin Zone" - a remote offshoot of the Russian River drainage; Knights Valley, a small, picture-book corner separating the upper end of the Napa Valley from Alexander Valley; and Northern Sonoma - all of the county that drains into the Pacific, Sonoma Coast, Sonoma Mountain and Sonoma Valley.

Room for growth

Another good thing about Sonoma is that land is half the price it is in Napa. You're talking roughly $50,000 (£33,025) an acre compared with $100,000 (£66,050) an acre in Napa (unplanted), which is reflected in many of the wines' prices. Newly released Napa Cabernets can hit $125 (£82.56) a bottle, whereas Sonoma's top wines are generally half that (excluding Jordan, Peter Michael, et al). And Sonoma isn't as planted out as Napa is. In fact, says the oenology department at the University of California's Davis university, Sonoma has the capacity to double its plantings of vines.

And then there's the talent. Young, go-getting wine-makers are given more freedom to do their own thing in Sonoma, with larger, more established wineries lending an ear - and a press. One thing is certain: there is a maverick streak running through the county.

Take Erich Russell. He's a wine-maker, fork-lift truck operator and payroll administrator at his winery, Rabbit Ridge, near Healdsburg (The Winery, 020 7286 6475). And before you ask, there are no rabbits at Rabbit Ridge. "I did see one a year ago," offers assistant wine-maker Mike Kuimelis. "It was Erich's nickname at school because he ran fast."

Russell bought the property in 1981, starting out with one barrel of Zinfandel. He now makes 200,000 cases of 50 different wines. There's a stunning Viognier 1998, $15 (£9.90); a cracking Barbera 1997 Grand Reserve, $25 (£16.50); and Sangiovese 1998 Grand Reserve, $25 (£16.50). "Sangiovese is really catching on here," says Kuimelis.

While Cabernet dominates in Sonoma, with Pinot Noir close on its heels, there has been a flurry of plantings in recent years of Italian and Rhône varieties. Russell is really known for his Zinfandel, though - the 1997 Old Vine Reserve, $32 (£21.13), is particularly good.

The Dry Creek Vineyard is also hot on Zinfandel. Again, the Old Vine is the best. Old Vine isn't a regulated term, but the unwritten rule is that vines must be at least 50 years old before they can become Old Vines. "It's a funny variety," says Dry Creek wine-maker Jeff McBride. "Zinfandel is a bit like human beings. When young it's a bit schizophrenic, producing inconsistent quality. Once over 10 years old it simmers down and starts to produce a consistent crop."

Dry Creek Valley is seven miles long and three miles wide, with soils ranging from heavy alluvial to gravelly-clay loam, with a high manganese content. From May to October the fog rolls in off the Pacific - only 30 miles away as the crow flies - cooling down the vines at night. Summer temperatures are in the 90s Fahrenheit.

There are now 30 wineries in the Dry Creek Valley, but Dry Creek Vineyard (Alivini, 020 8880 2525) was the first, setting up camp after Prohibition. Says McBride: "One of the things that sets Dry Creek apart is that we want to try new, fun things."

McBride makes 12 other wines including, surprisingly, an admirable Chenin Blanc. "In California, we can try just about any good thing that comes along, and sometimes it works. We haven't got the appellation restraints of other countries, but we've really caught up quickly with the rest of the world."

Dry Creek's 1997 Merlot is a case in point, as is the Meritage [a trademarked name for US wines made from a blend of varieties à la Médoc and the Graves]. "Californian Merlot and Cabernet has a tendency to turn to chocolate. Cabernet Franc maintains the fruit characters in those varietals. A chocolate-covered cherry is better than just straight chocolate," quips McBride.

Just down the road are Dry Creek's famous neighbours, the Gallo family (E&J Gallo Winery Europe, 01895 813444). The Frei Ranch vineyard is their Sonoma nerve centre. The Gallos own 750 acres of vineyard here, with a further 2,750 acres spread out across eight other vineyards in Sonoma, making it one of the biggest in the county. A sea of stainless steel emerges, startlingly, from behind a row of oaks.

"It's an oenological Disneyland, isn't it?" says Gina Gallo, proudly. "Yeah, we've got lovely kit here." Visiting wine-makers drool over the "kit". I counted 20 rotary fermenters, and lost count on the tanks. The barrel room is cooper heaven, with 60,000 barrels. There's Hungarian, Russian - even Chinese - barrels using different yeasts and fermentation practices. "My dad is a huge supporter of experimentation," she continues. "It's a big cost factor, but we'll make better wines in the end. What we want is to make boutique-style wines on a larger scale. The concept of the smaller the better doesn't wash with Gallo."

And before you dismiss the UK's number-one brand for your restaurant, consider this: a Sonoma Gallo wine is one of London restaurant Leith's top-selling wines.

St Francis may have only eight rotary fermenters to Gallo's 20, but it's still a major player in Sonoma. Wine-maker Tom Mackey likes rotary fermenters. "I've seen what they are doing with them in Australia. You get softer tannins," he says. St Francis (Hatch Mansfield, 01753 621126) makes 28 wines in all, including eight different Zinfandels, four Merlots, a Viognier, Sangiovese and a port. We're sitting in St Francis's new Sonoma Valley winery in Wild Canyon, funded by business partners the Kobrand Corporation. The business was founded in 1971 by a furniture salesman, Joe Martin. Mackey joined in 1983 when St Francis launched its own label. Kobrand also coughed up for Nunn's Canyon, a vineyard from which Mackey has being buying his reserve fruit for the past few years.

Tasting through the range, comments jumped from good to excellent, back to good again. Best were the Sonoma County Merlot 1997, the 1996 Reserve Merlot, the 1996 Reserve Cabernet Sauvignon and the 1997 Old Vine Zinfandel. Best of all were the prices - about £12.99 (retail) and £17.99 for the reserve wines. "People who raise prices only set themselves up with wine critics when they have a bad vintage," warns Mackey.

Value for money

Joel Peterson won't raise prices either. The wine-maker/owner of winery Ravenswood (John Armit Wines, 020 7727 6846) is adamant about this. He could charge three times as much if he wanted - the demand is certainly there. "But I say, why? I don't need any more money. The grapes aren't any more expensive. And my employees can still afford to buy my wine," says Peterson. His most expensive wine is $32.50 (£21.46), just recently up from $29.50 (£19.48). "But that's only because I had to replant the vineyard," he explains.

From 360 cases of Old Vine Zinfandel in 1976, he has grown to a 300,000-case operation, making 43 wines - among them Cabernet and Syrah. But Zinfandel is the main player here, from specific vineyard sites. Everyone has a favourite (mine is Belloni). After selecting the best block of grapes from the family-owned vineyards, Peterson pumps straight from the crush pads into redwood tanks. He uses open-top fermenters, wild yeasts and three weeks' fermentation. "The wines aren't brutally tannic, because the longer fermentation softens things down," he explains.

After fermentation, the wines head straight for medium-toast French barrels - "Nevers, I like the sweetness" - for up to two years.

Will Sonoma go the same way as Napa? "Oh yeah, it already is. But we are still so much more cowboy than Napa. It's a farming community here with only a handful of yuppies." n