Growing grapes on a steep hillside is quite challenging. First of all, planting along the hillside requires terraced farming. The soil is infertile and the drainage systems are often complex.  Stressing for water, the grapes often have smaller berries and higher concentration of fruit. The sun exposure is the longest in a mountain side vineyard. The more sun that the grapes receive equals higher quality of fruit produced. 

During the spring season, sometimes the mountainside fruit will not be endangered by frost that occurs on the Valley floor. High altitude fruit ripens slower due to the colder nights and impact of the air flow. 

During harvest, the grapes coming into the wineries are often lightly pressed, limiting the concentration of tannins. Most mountain wineries in the Napa Valley expertly grow Cabernet and other robust Bordeaux style varietals. The high altitude (American Viticulture Area) AVA’s of Napa Valley are Howell Mountain, Atlas Peak, Diamond Mountain District, Spring Mountain, and Mount Veeder. Next time, you take a sip of wine from a mountainside winery, ponder the amount of energy that went into that glass.