Is Carneros America’s Greatest Chardonnay Region?

Some of the best American chardonnays we've tasted in the last year have come out of an American Viticultural Area (AVA) shared by Napa and Sonoma counties in California, just above San Pablo Bay. You probably already know it: Los Carneros.

The success of chardonnay produced in Carneros can be attributed to both terroir and clonal selection, alongside growing and winemaking decisions. Its proximity to San Pablo Bay gives this southern Napa/Sonoma region a cool, windy mesoclimate. In contrast to sheltered regions of the valley further north, there is little protection from the Pacific Ocean and its cold, wet winds, resulting in the foggy mornings so particular to Carneros.

Coastal influence, fog and wind varies in different subzones. Tor Kenward, owner and winemaker of Tor Wines, prefers sites that “are in some way exposed to these winds, for they are cooler sites than those that are protected.” Sites closer to the coast are also more humid and thus more prone to mildew pressures and to botrytis later in the growing season. This in turn influences vineyard management.

For instance, grapes in Newton Vineyard’s Carneros Beckstoffer Lake Vineyard are grown in a more open canopy to relieve disease pressure, resulting in ripe grapes that retain natural acidity. The region overall, according to Alberto Bianchi, head winemaker of Newton, is “where we get the backbone of freshness, the tightness” compared to the roundness contributed by fruit from Rutherford and warmer areas in Napa Valley.

The soils also play a significant role in terroir. Carneros' deep soil, in many cases water-retaining clay, creates an environment where plants undergo less hydric stress that is common throughout the valley.

“Chardonnay is a variety that we don’t necessarily need to stress too much,” added Bianchi. He also said this is incidentally well-suited to merlot too, which may be a grape to keep an eye on from this region, although we have been less impressed with merlot in our tasting from here and prefer pinot noir, like most people.

Of course, the grape itself is central to excellent Carneros chardonnay. As Tor said, “Chardonnay is a winemaker’s wine, a tightrope walk of knowing when to pick, what oak to use, and many nuanced decisions that greatly influence the wine.” We agree entirely.

Clonal selection is of great importance when it comes to top chardonnay: lower-yielding clones, with small clusters, such as the Wente and Calera used in Tor’s wines, have a high skin to juice ratio. Tor said, “With many of the newer Dijon Clones [we] have not had the success we have had with heritage selections of Wente and Calera clones.”

Guillaume Boudet, winemaker at Hyde de Villaine, also emphasized the importance of “selections naturally producing lower yields, small clusters and small berries, enhancing the true characteristics of the varietal and the site.”

The focus on lower yields by top estates has enabled the production of concentrated chardonnay in 2018, a bountiful vintage where overcropping was a risk in California. Use of quality clones, careful vine management and crop thinning “allows us to retain focus, vibrance, and concentration in the wines, even with above-average yields”, Guillaume said.

With an ever-increasing emphasis on detail, chardonnays from Carneros have a role to play not only in continuing the region’s outstanding reputation, but globally too. James Eyer, general manager at Hyde de Villaine, said: “As the wine culture of the USA and the world continues to grow, wine of elegance and distinction will become highly coveted ... and consumers that believed they disliked chardonnay will be reintroduced to what I believe is the true expression of the varietal.”

Below is our list of our Top 10 Chardonnays from Carneros tasted over the last year. Each winery has been limited to one wine.

- Claire Nesbitt, assistant editor