Where the rest of the world stops making wine...Bolivia starts.
Anyone who has spent time traveling or living in high altitude understands how much it can affect us. The change in environmental conditions produces enormous effects on the human body, and for some people high altitude can be debilitating. The most immediate effect for humans is the reduction in available oxygen at increasing levels of altitude, which can make you feel like you have the flu or even the worst hangover of your life. After living for three years in La Paz at around 3,500 meters above sea level, I can tell you first hand that living at altitude has its challenges.
High altitude living isn’t just about oxygen; there are a wide variety of environmental factors that can cause significant stress such as ultraviolet light exposure, dry air, and drastic temperature changes. Humans generally should avoid stress, however in winemaking stress is key. It is said that stressed vines produce better wine. The more the vine has to work to survive, the better the quality of fruit it tends to produce. This is often cited as a reason to avoid irrigating vineyards; farmers believe that dry farming vines requires them to dig their roots deeper in order to access water. This not only makes them more resilient to periods of drought, but it also is thought to give them better access to different soils and nutrients that help create complex wine.
Those that produce wine in higher altitudes, say above 1,500 meters (4,921 feet), also believe the stress of these environments positively affects the vines. There is no doubt that any living thing is exposed to more stress at these elevations. Biggest stress factor is likely that of exposure to higher levels of ultraviolet rays (UV). If you have ever gone skiing and suffered sunburn on a sunny day on the slopes, you will be familiar with the intensity of the sun at elevation. As you go higher up in elevation there is less atmosphere to filter out the harmful UV rays. According to the World Health Organization, UV levels increase by 10-12% for every 1,000 meters (3,280 feet) of altitude increase. For humans this means that we need to protect our skin from sunburn, either by wearing appropriate clothing or apply sunscreen. Plants need to adapt to these conditions as well; Ultraviolet rays can damage leaves or fruit causing problems for photosynthesis or reproduction.
Grapevines react to this environmental stress in a few different ways. To learn more I interviewed Roberto Aguilar Jerez, viticulturist at Bodega Uvairenda, a winery located in Samaipata, Bolivia that grows grapes at 1,750 meters (5,741 feet) above sea level. “Grapevines need to protect their leaves from the UV rays”, says Roberto, “so they grow a thin layer of a wax-like substance on the leaves preventing sunburn.” Samaipata receives an even higher dose of UV rays due to its location at a latitude of 18º. As you get nearer to the equator there is less atmosphere between you and the sun, which is why tropical locations experience higher UV exposure. Bolivian wine regions are located between 18º and 21.5º latitude, which in addition to the high elevation environment creates extra stress for grapevines. It is thought that this extra stress is good for challenging the grapevines, much like water stress, helping to create complexity in the wines. This reaction is significant, but the most interesting result happens within the grapes themselves.
Though we often think that the purpose of the grape is to be eaten or to make wine, this is a rather anthropocentric view of the world (I love nerdy words!). The purpose of the grape, as with any fruit is to spread the plant's seed, to reproduce. The seed, however, is a fragile thing, and is also susceptible to damage from the increased UV rays at high elevation. UVB rays are able to damage the DNA of cells, and in order to protect the seed grapevines react by producing fruit with higher levels of polyphenols, such as tannin and resveratrol. These compounds act in a way similar to the compounds found in chemical sunblock, preventing them from reaching the cells of the seed so damage won’t be done. It has also been observed that grapes grown in high altitude tend to develop thicker, more resilient skins, helping to protect the precious seeds. Thicker skins will yield more deeply colored wines with potential for greater concentration of flavor and aroma. Much of the flavor and aroma for any given wine comes from the grape skins, so having thicker skins will generally lead to wines of more aromatic intensity.
It should also be noted that thicker skinned varietals are favored in these regions, such as Malbec, Syrah, Tempranillo, Cabernet Sauvignon, and the new favorite of Bolivia: Tannat. Tannat not only has thick skins, but it has been show to naturally have higher levels of polyphenols than most other grape varietals. These varietals arrive in the high altitude already equipped not only to survive, but also to thrive in these environments. Research has shown that these polyphenols are associated with cardiovascular health and longevity. For this reason, Marco Taquichiri of the Universidad Autónoma Juan Misael Saracho in Tarija, Bolivia has been conducting studies to determine just how high these polyphenol levels can reach. Through these studies, it has been shown that resveratrol levels in Bolivian wines under certain conditions can reach up to 10 times as many when compared to lower elevation regions. Though there is still a great deal of research to be conducted, there is promising evidence showing that these wines can help contribute to heart health.
Next to UV exposure, there is another factor that is very important to grape growing in high elevation. Wine nerds are often heard spitting out geeky terms, but one is often brought up when discussing high elevation wine: diurnal shift. This is essentially the difference between the highest and lowest temperature during a given day. High altitude growing regions generally experience high diurnal ranges, experiencing warm, sunny days and cool, fresh evenings. In the different growing regions of Bolivia it is common to experience a difference of 15 degrees Celsius (around 30 degrees Fahrenheit) during the course of a day. While the sun is out the vines will produce sugar through photosynthesis, creating the ripeness necessary for eventual alcoholic fermentation, and for wines with pleasant, ripe fruit character. During this process, respiration occurs causing a small loss of malic acid, one of the natural acids present in grapes, which provides structure in the final wine. Cooler temperatures at night slow down respiration and maturation, helping the grapes retain this acid and thus creating a more balanced and integrated wine. Though this is not a phenomenon unique to high elevation regions, it is certainly an important element in the overall terroir of a growing region.
So what does this all mean when it comes to winemaking? First and foremost, grape growers should be selective about what kinds of grape varieties they are planting in their vineyards. Certain noble varieties that can handle the challenges of high altitude, such as Cabernet Sauvignon or Syrah, will find a unique expression in these regions. There seems to be, however, greater potential in lesser-known grape varietals. In the high altitudes of Bolivia, growers favor traditional grapes like Mission and Muscat of Alexandria, both known for being resilient and adaptable. Singani, the traditioanl Bolivian Muscat based brandy, must be made at elevations over 1,400 meters (4,593 feet) in order to be legally called Singani. while newer plantings are generally thick-skinned varieties like Tannat, Malbec and Petit Verdot. Varietals like these were often used as blending grapes in Europe, where their thick skins and high polyphenols provided structure and color for blends in regions like Bordeaux. These grapes were rarely used on their own, producing wines that are too tannic or lacking ripe fruit character. Malbec is a great example of a grape that lost almost all of its plantings in France, but thrives in high elevation regions throughout Argentina. Malbec is now known for being the most widely planted grape in Mendoza (850-1,520m / 2,800-5,000ft), but it is planted even higher up in the northern region of Cafayate (1,700-3,100m, 5,600-10,200ft).
High elevation growing regions are found in Europe, but the highest top out around 1,400 meters (4,593 feet), such as the Vigna Gabriella, an experimental vineyard located in the Dolomites in Italy. New World winemakers are pushing the limits of high altitude winemaking, planting vines in some of the most remote, challenging environments. Winemakers in Chile, Peru, Bolivia, and Argentina are reaching previously unimaginable heights, such as Colomé’s vineyard at Finca Altura Máxima located at 3,110 meters (10,206 feet) in Argentina’s northern wine region of Salta. In 2018 Guinness World Records awarded the title of highest vineyard to the ‘Pure Land and Super-High Altitude Vineyard’ in Lhasa, Tibet, located at an elevation of 3,563 meters (11,689 feet). Though only about 66 hectares (163 acres) of grapevines are planted here, the owners are learning more about the challenges and potential successes of making wine in these extreme landscapes. These vineyards will certainly help us to learn more about the effects of high elevation on grapevines and help us push the boundaries of viticulture.
So now for the big question: does high altitude wine taste better? The simplest answer is: it tastes different. Taste is such a subjective quality, that it is impossible to say that one thing tastes better than another, but we can say for certain that high altitude winemaking regions have the potential for creating amazing wines with unique characteristics. The combination of ripe fruit character, bright acidity, high antioxidant levels, and story all can help make great wines, but the beauty of wine is that each of us can interpret and enjoy wine in a unique way. Just like anything in life, be open to something new and go get your hands on some high elevation wines to make your own assessment.
Aguilar Jerez, Roberto. Personal Interview. 5 March 2018