Compared to the humidity of a London heatwave, the climate of northern California is a dream: revitalising dry heat with miraculously predictable cool nights. Vines respond so well to these dry conditions with alternate warm and cooling influences that only Chile rivals California for the ease with which healthy grapes can be ripened there. The key to all this of course is the Pacific which obligingly blows cool fogs onshore as temperatures rise inland.
The extent of fog incursion is almost wholly determined by what lies between the vineyard and the ocean. I spent a day the week before last in a particularly chilly spot, the south west corner of Sonoma's Russian River Valley where, thanks to the breadth of the famous Petaluma Gap to the west, you can see the fog rolling in until late morning and again not too late in the afternoon. It would be great if this fog-cooled corner of the world matched a precise appellation but, as so often with AVAs, the American answer to Appellation Contrôlée, that is not the case. After 10 years of negotiation the Russian River Valley AVA was last year extended south to include much of this especially foggy cool corner, Green Valley and the Sebastopol Hills (where there were no vineyards when the AVA was originally conceived more than 20 years ago), but it still also includes the much, much warmer Chalk Hill sub AVA way inland to the north-east as well an overlap with the hot Alexander Valley. Not that Green Valley offers an exact match with the most fog-prone parts of Russian River Valley, although at least it is a great deal more homogenous than the vast Sonoma Coast AVA to the immediate west, described to me by locals variously as a "stupid", "baggy"and "embarrassing" appellation. It extends about 80 miles down the coast and well inland from well north of Russian River as far south as San Francisco Bay encompassing a huge variety of different viticultural conditions.
But these are the carpings of someone involved in trying to map the world of wine. Wine consumers should concentrate on the extremely palatable fact that the majority of grapes grown in the Russian River Valley have been subjected to more reliable cooling influences than many of their California counterparts and that many of the wines produced have not just the richness we associate with any fine California wine, but also real structure and refreshing citrus-like acidity. In fact Chardonnay grown on the valley floor, where fogs can persist until well into the day, can ripen so slowly that the grapes are not picked until the end of October (weeks later than Burgundy) and the acidity is still so high that wines have to be softened by 100 per cent malolactic fermentation. Little is predictable here. As Dan Goldfield of Dutton Goldfield pointed out to me on a hurtle round the region, "our ripest vintages are usually our coolest because if we get past any August heat spikes we can keep the grapes on the vine long into the fall". (Did I mention that California is not, unlike much of Europe, plagued by autumn rains?)
Contrary to most wine regions, where growers head uphill to seek lower temperatures and a longer growing season, the higher the vineyard above the fog line, like those of the revered Marcassin between Russian River and the coast, the warmer it is likely to be. Local growers are planting Syrah, for example, on the upper slopes, but it all depends on the precise position relative to the ocean, its altitude and orientation. Growers as experienced as Marimar Torres of Green Valley and Joseph Phelps of the Napa Valley have found the yields in their new plantings nearer the coast almost uneconomically low, and Phelps has recently drafted in Pascal Marchand of Burgundy to give some much-needed advice.
The landscape is quite different to the highly developed Napa Valley over the Mayacamas Mountains to the east. The apple orchards that once provided a living here can still be found, even if most of the apple processing plants have been transformed into custom crush facilities for that majority of Russian River producers who do not own their own wineries. Roads wind between ancient oaks. Oleanders, lupins and poppies grow wild in the hedgerows and reassuringly ramshackle dwellings predominate.
Rochioli is the gold standard name in Russian River. The family have great vineyards and such a high reputation for their wines and grapes that they sell every bottle and have a long waiting list for every grape they don't vinify themselves. Williams Selyem is one of very few other producers allowed to buy Rochioli grapes and, after a glorious period in the 1980s and early 1990s, are recovering their status after having been acquired by John Dyson of Millbrook winery north of New York City in the Hudson River. Gary Farrell is another producer with a hard-won reputation. All three of these producers are in the original, slightly warmer reach of vines along the Russian River itself.
But there are now 350 Russian River growers in all and almost 80 labels as more investors are attracted by the special characteristics of the wine produced here. Land prices have quadrupled in the last 10 years, although are not as high as Napa Valley's. Bigger companies busy planting here include Gallo and distillers Brown Forman, while those who own the Mark West label, which began life as a Russian River Pinot Noir, are now sourcing Pinot not just from the Central Coast 250 miles south but also from Corsica, so strong has been the Sideways effect on demand for the red burgundy grape.
In this relatively cool region, the dominant varieties are Pinot Noir and the Chardonnay that predated it, planted in the 1970s during the white wine boom. Merry Edwards, the doyenne of the region, has proved that it can produce unusually age-worthy Sauvignon Blanc too however, while the likes of Joseph Swan have long made the most of some of the Zinfandel vines planted by Italians who arrived to log railway sleepers in the late 19th century around the half-horse town of Occidental.
The biggest Russian River specialist vineyard owners are the Dutton family. Having seen the Dutton ranch name on scores of bottles over the years, I fondly imagined it was one vineyard. In fact the family own or control 80 different ranches totalling well over 1,000 acres of vines in some very varied terroirs. The Duttons, mother Gail and sons Steve and Joe, all live in what some call the Valley of the Duttons just west of the town of Graton.
Climatologists are unsure of the effect of climate change on fog incursions along the Pacific coast, but admit that it could bring an extension of the fog belt and possibly even shorten the daily fog-free period. Russian River Valley may yet make even more elegant wines.
Recommended Russian River Valley wines
(in approximate declining order of preference with recommended US retail prices)
Dutton-Goldfield, Rued Vineyard Chardonnay 2004 $45
DuMol Syrah 2004 $50
DuMol, Chardonnay 2004 $48
Lynmar, Quail Hill Vineyard, Chardonnay 2004 $40
Walter Hansel, RRV Estate Chardonnay 2004 $28
Dutton-Goldfield, Sanchietti Pinot Noir 2004 $55
Marimar Estate, Cristina Selection, Don Miguel Estate Pinot Noir 2003 $47
Gary Farrell, Cresta Ridge Vineyard, Chardonnay 2004 $38
Merry Edwards, Olivet Lane, Methode à l'Ancienne Pinot Noir 2004 $57
Lynmar Pinot Noir 2004 $36
Joseph Swan Vineyards, Trenton Estate Pinot Noir 2002 $45
Russian Hill Estate, Tara's Vineyard Pinot Noir 2004 $42
Merry Edwards Wines, Sauvignon Blanc 2005 $27
Williams Selyem, Allen Vineyard Pinot Noir 2004 $75
Dutton Estate, Dutton Ranch Chardonnay 2004 $35
Ferrari-Carano, Fiorella Chardonnay 2004 $37
D'Argenzio Zinfandel 2002 $28
Acorn Winery, Alegria Vineyards Zinfandel 2004 $32
See also full tasting notes and scores on 80 Russian River Valley wines.