(Los) Carneros is one of California's oldest and most celebrated viticultural areas. It was first planted with grapes in the 1830s, and now ranks among the world's top regions for Pinot Noir and Chardonnay, particularly when the two varieties are combined to make sparkling wines in the traditional method. (© Copyright material, Wine-Searcher.com)
The cool, windy, foggy mesoclimate here proved extremely challenging for the early vineyard (problems compounded by the combined effects of phylloxera and prohibition) and it was not until the late 1970s that the area's vineyards began to achieve any consistent quality and recognition. By the late 1980s many hundreds of acres of vineyard had been planted in the AVA, and the reputation of Carneros wines began rising to its current glory.
Carneros' winemakers were quick to realize the potential of their terroir for cooler-climate wine styles. Besides varietal Pinot Noir and Chardonnay, they also make high-quality sparkling wines from the two varieties. In the 1980s, Champagne house Taittinger chose Carneros as the location for its Californian presence (Domaine Carneros), at around the same time as Cava magnates Jose and Gloria Ferrer started their sparkling wine production here.
Carneros Pinot Noir has traditionally been lighter and tighter than those from other Californian regions, with notes of berries and herbs. rather than anything deeper and more opulent. This makes it particularly obvious when a winemaker has been over-enthusiastic with the use of oak. Likewise, Carneros Chardonnay is typically more elegant than other Californian Chardonnays, with crisper acidity and fresh stone-fruit aromas. It is easy to see why a fair proportion the district's grapes are purchased by wineries from warmer regions, for use in sparkling wines. These two varieties (the 'King' and 'Queen' of Burgundy) dominate the vineyards here, jointly accounting for around 90% of the total vineyard area. In warmer, sheltered spots, mostly on the Napa side of the AVA, they are sometimes joined by small quantities of Syrah, Cabernet Sauvignon and Merlot.
Carneros is situated at the southern tip of the Sonoma Mountains, at the meeting point of Napa Valley and Sonoma Valley. Thus the AVA is divided between America's two most famous wine-producing regions – the eastern half in Napa, the western half in Sonoma. Many producers label their wines as "Carneros Napa Valley" or "Carneros Sonoma Valley", depending on which side of the county line they are located.
The official Carneros AVA (created in 1983) covers an area of 90 square miles (230 square km) on the southernmost foothills of the Mayacamas and Sonoma mountain ranges. This topography here – or rather the cool, windy mesoclimate it creates – is intimately connected with the style of wine produced there. As the mountains disappear (they drop down into San Francisco Bay before rising again in Contra Costa County), so does the protection they provide from the cold, wet winds which blow in from the Pacific Ocean, 30 miles (50km) west of Carneros. This gives Carneros a much cooler, wetter climate than that found further north in the sheltered valleys.
The hiatus in the Coastal Ranges described above is known as the 'Petaluma Gap'. It is a key feature of southern Sonoma's topography and climate, and provides climate-cooling influences not just to Carneros, but to other AVAs, including Sonoma Coast, Russian River Valley and even the southern end of Napa Valley.