Napa Valley is known throughout the world for being a premium winemaking region in the United States. The mild Californian climate coupled with the good soil properties has fueled a winemaking culture that brings tourists in from the far reaches of the globe.
What makes Napa Valley so good for making wine?
Napa Valley has mild winters and hot summers, fertile, volcanic soil, and steep slopes. All combined, Napa Valley rivals older, larger winemaking regions in France, Italy, and beyond.
Here are some of the reasons that Napa Valley is perfect for growing the grapes that make wine:
Grapes grow best where summers are hot and winters are mild.
Very cold winters in the Northern United States can shorten the growing season. Unpredictable winter storms can bring early frosts that could damage or ruin entire crops. Frost, snow, and frozen ground can damage the vines or roots. Grapes need about 150 to 170 days during their growing season to produce a good harvestable crop.
Humid weather in the Southeastern United States can promote diseases, molds, and funguses. Powdery mildew, for example, starts as white powdery spots on the leaves that gradually grow to kill entire plants. These types of mildew thrive in damp conditions. Adequate airflow and dry air help keep them at bay.
Even too hot of weather can stifle the growth of the vines. High temperatures early in the growing season can make the leaves smaller. In the middle of the season, heat can reduce the amount of fruit the vines will produce. As the grapes finish growing later in the season, high temperatures can prohibit them from ripening, which will cause discoloration in the fruit.
Napa’s climate is the perfect mix. The winters are mild with highs in the mid-50s during the winter, and lows in the mid-30s. Frost may not even occur some winters. The growing season can be over 200 days. During the summer, the weather tends to be very hot and dry.
Winegrowers have noticed that the summers are getting hotter, dryer, and longer, causing some concern that their vines may become heat-stressed on a more regular basis annually. Vinters have begun to express concerns that climate change could be detrimental to the perfect climate that makes Napa Valley an ideal grape growing region.
Grapes grow best in a soil type called sandy loam, but other soil types such as clay loam are ideal for different varieties. Sandy loam is a well-draining soil that helps but contains a lot of organic matter, which provides nutrients to the vines. Clay loam has a higher concentration of clay than sand or silt.
One test to see if the soil drains well enough to grow grapes is to fill a hole with water and if the water disappears into the ground within a day, the soil had adequate drainage. However, if it drains too quickly, the vines may not be able to absorb enough water fast enough before the water drains away.
Drainage is important because if the roots of the vines stay too wet for too long, they will rot. Vines are often planted on south-facing hillsides to prevent water from ponding between the rows of vines while getting plenty of sunlight. However, sometimes the soils can be used to directly impact the flavor of the grapes. Some soils are better suited to different varieties of grapes.
Napa Valley has a wide range of soil types. The valley floors have very fertile soils that lend to crops with large fruits. On the rocky hillsides, the vines have to work harder to survive, which results in grapes that a smaller but more packed with concentrated flavor. Napa Valley is known especially for Cabernet Sauvignon, where the soil helps produce wines that are very fruit-forward in the valley regions, and smoky and peppering from the elevated slopes. Merlot, Chardonnay, Pinot Noir, Sauvignon Blanc, and Zinfindel are all popular varieties used to make single-variety wines as well as world-class blends.
Napa Wine Culture
Other regions throughout the county may have great conditions for growing grapes for wine. However, Napa Valley was home to one of the first commercial vineyards in the 1850s, with the nearby Sonoma area providing resources and transportation for goods. The Napa Valley region exploded with growth in the 1880-1890s.
While it was difficult for Napa Valley winemakers to export their wines even as far as the East Coast during that time, with the influx of settlers from the Gold Rush, California wines took off. It wasn’t until the 1970s though that Napa Valley wines began to rank competitively when a California wine won in a blind taste test against nine French judges, now known as the “Judgement of Paris.” Since then, California wines earned the right to compete alongside world-renown wines and wine regions.
These days, tourists and wine tasters from around the world flock to the region to enjoy days of wine tasting adventures. Compared to other wine tasting regions around the world, the Napa Valley region caters to hospitality. There are more restaurants, for example, per capita than any other wine tasting region in the world. This helps make Napa Valley as much a vacation destination where wine tasting is as much as an activity as winemaking is a way of life.
Despite the popularity of tourism, the Napa Valley region has passed regulations that help prevent the area from becoming overdeveloped. The protection, called the Ag Preserve, helps keep developments, like overly large freeways, from taking over some of the oldest vineyards in the area. The Ag Preserve helps ensure that these lands, that are so well suited for growing the grapes the make wine, are preserved to keep growing their world-class crops.
Napa Valley’s climate, soil, and culture make it a perfect region for growing and producing wine. The variety of soil and slopes produce wines that compete on an international level, bringing in tourists from all over the glove.