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Los Carneros AVA

by David on June 30, 2009

The name Los Carneros tells you about its agrarian history – it translates from Spanish as “The Rams,” referring to the many sheep ranches that dotted the country-side in the early days. For many years following repeal of prohibition, Los Carneros remained primarily an area of sheep and cattle ranching, while the upper valley was rapidly being planted to grapes. In spite of a history of grape growing in the 1800s, some believed there was not enough water, and that the soil was too shallow and impermeable to support commercial vineyards.

Finally, in the early 1960s, a few brave pioneers began planting vines, and, as they say, the rest is history!

Today, the Carneros AVA (American Viticultural Area) is renowned for Chardonnay, Pinot Noir, and sparkling wines of elegance and distinction, and is generally accepted as the best part of Napa Valley for growing them. It gained AVA status in 1983. As with all AVA’s, the minimum requirement is 85% Carneros grapes to put the Carneros AVA on the label.

Why do we have AVAs? Throughout the country the wines of certain regions have stood out, leading to an investigation of the mesoclimates1and soils that make the area and its wines unique. Growers and vintners within a specific region define its boundaries and give it a name (often historical or a reference to topographical features), or appellation, to set it apart. These appellations must be approved by the federal government.

Napa Valley was the first AVA approved in California as recently as 1981, reminding us how far the valley has come in a very short time. It’s a rather specific AVA (AVA’s vary radically in size), in that Napa Valley is only about 30 miles long, and a few miles wide. Many are unaware that Napa Valley produces less than 5% of California’s wine.

Generally speaking, the more specific the appellation, the more distinctive the wine is likely to be.

Almost as soon as the Napa Valley AVA was approved, the valley was further subdivided into more AVA’s based upon differences in soil, climate and wine character. This was a natural evolution, as we came to know the valley better and realized the wisdom of matching the right variety with the right place.

Cool climate, early ripening varieties, especially Chardonnay and Pinot Noir, shine in the Carneros. The San Pablo Bay near Los Carneros at the southernmost end of Napa Valley provides the foggy, windy air conditioning for the entire valley. However, as the valley progresses north, it moves away from the maritime influence. Consequently, heat loving varieties do well in the north, and the delicate, early ripening varieties are concentrated in the Carneros. For many years, winemakers have recognized that the uniformly cool, breezy microclimate throughout the Carneros region produces grapes and wines which share a common style.

The cool conditions lead to slow maturation, so the grapes are fully mature at lower sugar levels and higher acids, maximizing freshness while achieving great depth of flavor. This is the ideal situation for growing our signature aromatic, crisp, Goosecross Chardonnay.

The clay soil, once thought to be a possible detriment, has proven to be very favorable for high quality wine grapes. The clay tends to impact the vine’s vigor by restricting the development of the root system and providing just enough nutrients and water to sustain growth without excess development. Too much vigor can work against quality and lead to vegetal or bland tasting wines. Slight stress generally produces smaller, more flavorful grapes, because they’re less juicy, and the juice is watery.

Two clay soils, the Diablo and Haire series dominate the region. The yellowish-brown, Haire soils contain calcium from ancient marine deposits of sea shells, which is beneficial to grape vines. You can find these fossil shells today as you walk the vineyards. These soils are slightly alkaline, and have a very high clay content that provides good water holding capacity.

The more acidic, black Diablo soils are high in manganese, an essential nutrient for grape vines that helps plants to form chlorophyll. Diablo soils have a high clay content and good water holding capacity although they are slightly less permeable.

Haire and Diablo soils tend to alternate in a soil profile, suggesting that the grape vine adapts to a very different chemical environment as the roots grow from one layer into the next. The change in chemical environment slows the growth of the vine, restricting its vigor.

We’re fortunate that our Los Carneros vineyard includes some gravel and sand not often found in the region, interspersed with the clay soils, allowing for better drainage.

2004 marked the first release of a Carneros District Goosecross Chardonnay, and we have been gratified to find that it’s all that we hoped for and has been so well received. The wine reflects the elegance characteristic of its appellation of origin.

Regional statistics, Napa Valley Vintner’s association:

Climate: High temperatures during summer rarely exceed 80°F (27°C) and cool to the mid-50s (13°C) at night.

Elevation: 15 to 400 ft. (4.6 to124 m)

Lowest in Napa Valley: 18 to 24 inches (7.2 to 9.6 cm) annually


1. Meso-climate: The climate of a vineyard site, hillside or valley. The term “microclimate” is used in its place extremely often. Microclimate correctly refers to the climate immediately surrounding the individual vine canopy (or green growth) and clusters. Vineyard and canopy management will strongly influence the microclimate, but not the mesoclimate.

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