The Impact of Terroir in Howell Mountain Wine Country

In 1984, the Howell Mountain Wine Region was the first microclimate in the Napa Valley to be granted AVA status. Located in the Vaca Hills overlooking the town of St Helena, the region’s terroir is characterized by long, sunny days. Near the prohibitionist 7th Day Adventist town of Angwin, it may seem like an unlikely area to produce great wines. Nothing could be futher from the truth.

The AVA encompasses 14,080 acres of which only about 600 are planted with vines. Much of the region is either too steep or logistically inaccessible for viticultural production. The elevation ranges between 1400 and 2200 feet above sea level, with the majority of vineyards planted at around 1800 feet.

These vines are rarely exposed to the fog that regularly blankets the valley floor. Grapes are mainly grown on southwestern facing slopes that enjoy abundant sun exposure. The region has historically grown the red Bordeaux varietals (Cabernet Sauvignon, Merlot, Cabernet Franc, Malbec and Petite Verdot) as well as Zinfandel and Petite Sirah.

Despite these sunny days, daytime temperatures are generally lower than adjacent region located on the Napa Valley Floor. This is due to the higher elevation as well as a consistent breeze from the Pacific Ocean. These winds also keep humidity low and help to prevent mildew in the vineyards.

The combination of sun and moderating winds promote phenolic development as well as a relatively high level of acidity. Robert Craig Wine Cellars produces a well-rounded Cab from the mountain that is the result of this nuanced, balanced terroir.

The Impact of Terroir in Howell Mountain Wine Country

The Impact of Terroir in Howell Mountain Wine Country

The loamy, gravelly soils of the mountain drain very well. The top soil is made primarily of decomposed volcanic ash, volcanic rock, and iron-rich clay, and is very nutrient poor. Very little water is retained, leading to stressed vines and very flavorful grapes. In contrast, much of the soil on the valley floor is alluvial and fertile. Some of these vineyards have to be thinned to uphold fruit quality. This is not an issue on Howell Mountain.