Howell Mountain AVA
Howell Mountain, located within the Vaca range running along the eastern edge of the valley, received the first AVA (America Viticultural Area) in the Napa Valley viticulture region. The separate designation, created in 1983, reflects the unique microclimates, soils, and exposures that are found in the AVA, as well as the distinctive wines made from the grapes grown here.
Rising from 1400 feet to 2200 feet above sea level, this appellation is one of the few based on land contour. One of the reasons for this is that the 1400 ft. elevation demarks changing conditions from its surroundings. For example, during growing season, fog that typically blankets the valley below often clears at the 1400 foot level. This provides more hours of sunshine while the altitude keeps daytime temperatures cooler and nighttime temperatures warmer than the valley floor, allowing for more consistent and even temperatures. Also, although not a volcano itself, Howell Mountain received substantial fallout from nearby historic volcanic eruptions. Because of this, the soils on Howell Mountain are comprised of layers of compressed ash known as tufa; red, iron rich clay; and red and brown volcanic loam. Much of the area is also covered with rock: some close to the surface and easy to move, some deep and pervasive. Even though Howell Mountain typically receives twice the amount of rain as the valley floor, the soils have good drainage and poor water retention, unlike the valley floor, which has relatively few rocks, rich soils and good water retention.
The poor soils, abundance of rock and the dry, temperate climate found in the Howell Mountain AVA combine to create vines that are stressed, producing smaller clusters and berries and lower yields than their valley floor counterparts. Fortunately, however, this hostile environment results in concentrated and intensely flavorful berries. They exhibit a nose and taste profile that is unique to the AVA. This profile is expressed in the wine by robust earthiness, minerality and an intensity of fruit that is not found anywhere else in the valley. The wines tend to have depth and balance. This is the payoff for the difficult and tedious work that goes into the planting and cultivation of these vineyards, especially if farmed organically. The reward is found in the glass.
Bordeaux varieties and Zinfandel have historically done well and currently thrive here, Zinfandel being the earliest primary variety in the late 1800’s. It is interesting to track the beginnings of viticulture in this area as well as watch new vineyards and wineries add their mark. Although there is a distinct similarity throughout the AVA in the wines that are grown and produced here, planting and cultivation techniques and winemaking philosophies lead to vast variations in the end product. This helps create and maintain interest and excitement around the various vineyards and wineries, and broadens the expression of terroir.