How Does Altitude Affect Wine?
What makes grapes grown in vineyards set at higher elevations special compared to valley-grown grapes in the same region? It’s a combination of increase in solar rays, greater temperature fluctuations, scarcity of water resources and the elevation changes themselves. The Stonestreet Mountain Estate towers high above the Alexander Valley in the Mayacamas Mountain Range with vineyards ranging from 400ft. to 2,400ft. in elevation. With this substantial change, the estate showcases a dramatic array of mesoclimates on our many peaks, valleys and ledges which influence the complexity of our wines through these diverse growing areas. High elevation farming brings with it a number environmental challenges and limitations that all help shape the unique and highly-acclaimed wines of Stonestreet.
How Temperature and Solar Rays Affect Wine at Elevation
A wine’s tannin structure and acidity are predominately developed in the vineyard and are mainly impacted by the quality of that vineyard’s exposure to the sun and the temperature shift that vineyard sees from day to night. As you move upward in elevation, the density and intensity of the solar rays increase, meaning an increase in both direct sunlight hitting the vineyard and in temperature. High elevation mountain and hillside vineyards tend to receive more direct and concentrated sunlight – for every 1,000 feet gain in elevation, the level of UV rays increase by 10-12% - which forces the fruit to develop thicker skin, leading to greater color concentration and stronger tannins. Temperatures also increase exponentially as elevation increases. During the summer and fall, our mountain vineyards that are set towards the top of our estate can be up to 20 degrees (or more) warmer than those on the valley-floor leading to more concentrated flavor profiles in the fruit.
Higher elevation growing areas will also see a greater shift in temperature between day and night. Once the sun sets, temperatures in Alexander Valley drop drastically but this shift tends to be more pronounced at altitude. The cooler nights throughout our vineyards allow the grapes to conserve their acidity leading to more elegant, age-worthy wines and helps to lengthen the growing season allowing the grapes more time to develop on the vine.
Inversion Layer and Fog Line Influence Wine
The inversion layer around the Mayacamas Mountain range, which extends into both Napa and Sonoma County, falls between 1,600ft. to 1,800ft. in elevation, often resulting in a thick layer of fog below the inversion cap during the early morning which covers only a portion of our estate. A number of our vineyard sites (mainly our Chardonnay vineyards) are planted along this elevation and are influenced by both climate conditions. Because of this, we see a complex range in flavors between the “top and bottom” of these vineyard sites – a complexity that shines in the wines they create.
Mountain Precipitation and Water Runoff
Higher elevations are prone to more intense weather due to the way the storm systems hit the mountain ranges. Our mountain vineyards tend to see proportionately more rainfall then their valley floor counterparts, however, given the slopes of our hillside vineyards and natural runoff, that water never has a chance to soak in – reducing the amount of moister that makes it deep into the soil to feed the roots of the vines. This lack of surface water forces the roots to grow deeper, in turn stressing the vine which encourages the vines to put more energy into developing fruit rather than full, leafy canopies. This also influences the yields of our vineyards – average tons per acre of grapes produced – leading to fewer grape clusters per vine which in turn allows those clusters to develop more fully.
Farming Mountain Vineyard Grapes by hand
Due to the steeper slopes, vineyard orientation and terrain, we are forced to do everything by hand on our estate. Many vineyard management practices have been mechanized in the last few years to streamline the processes, but these machines do not fit down the narrow vineyard rows of Stonestreet and cannot traverse the steep terrain. Instead, we employee an extraordinary 100+ person vineyard team who take great pride in our vines. Though it may require more manual effort, the overall impact we have on the land is reduced allowing us to truly focus on our sustainability efforts. Our gentle approach helps minimize our carbon footprint and leads to higher quality fruit.
Giving Perspective to High Altitude Grape Vines
As mentioned, our Stonestreet Estate Vineyards range from 400ft. to 2,400ft. in elevation. To put that into perspective, that is nearly twice the height of the Empire State Building in New York City. There is only one building in the world that surpasses the height of our mountain estate – the Burj Khalifa in Dubai, United Arab Emirates at 2,717ft. Internationally, our mountain vineyards tower over many landmark buildings such as the Tokyo Skytree in Japan and the Eifel Tower in France. Within the United States, we commonly refer to notable buildings to offer a comparison to the various elevations of our vineyards – Willis Tower in Chicago (formally Sears Tower), the Transamerica Building in San Francisco and the Seattle Space Needle to name a few:
Overall, we see great power and intensity in the wines we produce from our mountain estate. For our Cabernet Sauvignons, we attribute these conditions to their signature robust tannin structure, balanced acidity and concentrated flavors. For our Chardonnay, the wide range of growing conditions translates to elegant and balanced wines with complex flavors and textures. No two vineyards are alike on our Stonestreet Mountain Estate Vineyards; they differ in everything from soil type, to mesoclimate, to elevation. Though the farming of high elevation vineyards may be challenging, our vineyard and winemaking team gladly tackle it every day and because of their dedication our vineyards offer us the best reward possible – beautiful wines that are worth enjoying and sharing.