Chardonnay plays a dual role as both the queen and the workhorse of Sonoma County wine. A pedigreed member of the “noble grape” club, Chardonnay dominates Sonoma County’s white wine category almost as much as it reigns over Burgundy, its ancestral home. But because of the widespread popularity of this very international varietal, Chardonnay always has to remain competitive: some of the most coveted and expensive bottles of Sonoma County wine are Chardonnay, as are the bulk of bulk of Sonoma’s affordable, everyday white wines—and all points in between.
Chardonnay Key Facts
Chardonnay was the fifth most widely planted grape in the world as of 2010, and in 2015 was the top white wine grape planted in Sonoma County, occupying more than 15,600 vineyard acres in Sonoma County.
The Chardonnay vine buds out relatively early, and has slightly rounded leaves similar in appearance to Pinot Noir. Grape clusters are small to medium-sized with round berries that turn yellowish-green after veraison, and may become yellow or brownish-green by harvest. Some clones of Chardonnay are prized for producing a “hens and chicks” (French vignerons call it millenderage) pattern of alternately large and tiny berries.
Primary fruit aromas and flavors in varietal Chardonnay range from lean citrus to sweeter Meyer lemon, from fresh yellow apple to baked apple, and typically in warmer growing areas, into the tropics with mango and pineapple.
Chardonnay: the Burgundian Backstory
Most white wine from Burgundy is 100% Chardonnay, but the varietal is rarely listed on the label (and only for value-driven wines when it is). White Burgundy is traditionally labeled with its appellation or village name: Puligny-Montrachet and Meursault are among the best known. Neighboring regions Chablis and Mâcon produce their own, distinctive styles of Chardonnay.
Perhaps because of its noble status, Chardonnay was long thought to be a variant of the highly regarded Pinot Noir grape, and it was often misidentified as Pinot Blanc. It did not help matters that it was also known by various other names: White Pinot, Pinot Chardonnay, and even Pinot Blanc Chardonnay. In the 1990s, DNA fingerprinting revealed that Chardonnay is the child of Pinot Noir and Gouais Blanc, a workhorse white grape from Roman times that made lesser wines.
Chardonnay in Sonoma County
Despite its good reputation in France, Chardonnay was slow to be adopted by Sonoma County wineries and grape growers. Legendary California professor of viticulture E.W. Hilgard mentions Chardonnay as “pinot chardonay” in his viticultural reports dating from the 1880s, around the same time John H. Drummond began to import Chardonnay and Pinot Noir to complement his successful Cabernet Sauvignon plantings at his Kenwood vineyard, now part of the Kunde Estate. But after Prohibition, the grape remained obscure.
Everything changed for Chardonnay one day in 1976, when, in a blind tasting since dubbed the “Judgement of Paris,” French wine experts judged Chateau Montelena’s 1973 Chardonnay the better of several white Burgundies from top vineyards in Montrachet and Meursault. Although Montelena is a Napa Valley winery, the majority of the fruit that went into the 1973 Chardonnay came from Sonoma County vineyards.
Today, no other white grape approaches Chardonnay’s total acreage in Sonoma County, second only to the vast plantings in Monterey County. According to the 2014 Grape Crush Report, Sonoma County growers receive the state’s second-highest price for their Chardonnay—indicating both high demand and quality.
Like Pinot Noir, Chardonnay rarely has to share a bottle with other grape varieties in a blend. Unlike Pinot Noir, Chardonnay is vinified in several radically different ways and often bears the signature of the winemaker as much as that of the vineyard or the region. The best Sonoma County Chardonnay makes it possible to appreciate both.
The “oaky, buttery Chardonnay” flavor profile, now an international wine style recognized in wine regions around the world, is the product of winemaking decisions and techniques. Very few white wines are aged in such a high percentage of new, toasted oak barrels as Chardonnay, and these barrels lend the wine aromas that range from campfire smoky to roasted almond to coconut.
The aromatic suggestion of butter or cream is a product of malolactic fermentation, an enological term that might not have escaped from the lab to the tasting room if it hadn’t been for Chardonnay. Most red wines undergo this process, in which lactic acid bacteria transform malic acid (the kind that’s prevalent in apples) into lactic acid (a softer, more creamy acid found in dairy products), but it’s rarely remarked upon. The process is blocked in most other white wines.
Adding to the buttery effect is a byproduct of malolactic (or ML) fermentation: diacetyl, which is also employed in “butter flavored” popcorn. Winemakers may select different strains of bacteria to heighten or lessen this effect, or they may rely on naturally-occurring populations. Cellar practices and temperatures add yet another dimension.
The aroma and mouthfeel of Chardonnay may be further shaped by “batonnage,” the French term for stirring the slurry of dead yeast cells that collect on the bottom of the barrel.
While the reported backlash against this style of Chardonnay is now more than 20 years old itself, “unoaked Chardonnay” has been promoted more recently. Crisp and refreshing, these wines are usually also made by blocking ML, but they rarely attract critical acclaim.
The main trend is toward a synthesis of styles: look at a winery’s technical data sheet for their Chardonnay, and you may find that it was fermented in 40% stainless steel (for example), while 60% was fermented in oak barrels, and 20% malolactic was blocked—the variations are unlimited.
Finally, Chardonnay is important in Sonoma County sparkling wine. Typically, California sparkling wine shows displays more primary fruit flavors than wines grown in the chilly Champagne region of France. But in the cooler regions of Sonoma County, the grape retains enough natural acidity to make vibrant brut and blanc de blancs sparkling wine.
Sonoma County’s Key Chardonnay Regions
Russian River Valley
A good portion of Chateau Montelena’s “Judgement of Paris” wine came from the Bacigalupi Vineyard, planted in 1964 off Westside Road. Also in the 1960s, Dutton Ranch was among the first to plant Chardonnay.
Within the AVA, the Green Valley of Russian River Valley region is a cool, foggy pocket where Chardonnay retains higher acidity for excellent methode champenoise sparkling wine.
Wineries: Bacigalupi, Rochioli, Dutton-Goldfield, Taft Street, Martinelli, Korbel, Iron Horse.
Somewhat of a catch-all AVA that encompasses much of the Russian River Valley and Carneros, Sonoma Coast also includes the proposed Petaluma Gap region and the new Fort Ross-Seaview AVA. Chardonnay grown in cool coastal zones often develops the acidity and structure needed to wear new French oak with grace.
Wineries: La Crema, Sonoma-Cutrer, Joseph Phelps Freestone, Marimar Estate, Fort Ross.
Sonoma Valley and Bennett Valley
Not much publicized as Chardonnay regions today, Sonoma Valley and its subapellation, Bennett Valley, are the site of several firsts in Chardonnay: In the hills above the town of Sonoma, Hanzell Vineyards pioneered temperature-controlled fermentation and the use of small oak barrels; in the 1980s, Matanzas Creek was a leader in the big, buttery style—and was able to charge a then-unheard-of price—but their style has refined with the times.
Wineries: Hanzell, Matanzas Creek, Landmark, Chateau St. Jean, Kunde, Buena Vista.
Temperatures in the Carneros are influenced by breezes from San Pablo Bay, making for a cool, windy, but relatively stable growing season. Chardonnay for sparkling wine is particularly important in the Carneros.
Wineries: Anaba, Ceja, Cline, Gloria Ferrer, Ram’s Gate.
Alexander Valley and Knights Valley
These are Sonoma County’s warmest growing regions, yet Chardonnay thrives here alongside Cabernet Sauvignon.
Wineries: Alexander Valley Vineyards, Jordan, Robert Young, Rodney Strong, Stonestreet, Stuhlmuller.
Find out more about Sonoma County's wine regions.
Written by Sonoma Insider James Knight.