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What altitude does to coffee growth?

· Coffee Facts
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What’s So Important About High-Altitude Coffee?

It is pretty common to hear people talk about the importance of growing coffee at high elevations. Advertisements for mountain grown coffee date back more than 50 years and coffee companies still brag about coffees that come from high elevations. It makes you wonder if there’s something magical about mountainsides or being far away from the sea.

As it turns out, the scientific data is equivocal on the subject. Some research demonstrates a difference in taste as elevation changes while some does not. Many people in the coffee industry, including this author, have experience that suggests different altitudes produce different cup profiles; coffees grown higher up tend to be more acidy and complex while lower elevations tend to be more intensely coffee flavored. If there really is a difference in elevation, what’s going on?

Any athlete will tell you that the air in thinner at higher altitudes. This is because there’s lower air pressure up there (the weight of all the air that presses down on everything), causing less oxygen to be present in any given breath of air. Plants, however, don’t seem to care much about this. While nobody has tested the effects of different air pressures on coffee plants, researchers doing space research (astronauts need to eat, right!?) have shown that lettuce leaves changed somewhat when grown in different air pressures. However, none of the research examines the taste. Radishes, on the other hand, barely responded at all to different air pressures (unless the air pressure is very, very low). More interesting, the flavor of radishes and some chemical markers that stand in for flavor, didn’t change when the radishes were grown in different air pressure conditions. Lettuce (leaves) and radishes (roots) are different types of plant organs than coffee (seeds), so it is hard to draw a strong comparison from these examples. However, considering the nature of the changes in lettuce and coffee being a seed, it is unlikely that air pressure is influencing the cup quality of coffee.

A change in air pressure is only one difference that happens at higher altitudes. The other is that the temperature drops. It has been well documented that temperature affects many aspects of plant growth and development across a range of species, including food plants like coffee. As air pressure seems not to be too important in influencing coffee’s taste, it is reasonable to assume, then, that the change in temperature at higher elevations is what is influencing our brew.

To support this, we must consider that, across the globe, temperature is influenced not just by elevation. A major factor is latitude. As the distance from the equator increases, temperatures at a given elevation decrease. While many factors influence the flavor of a cup of coffee, the temperature at which it grows seems to be one of them. Looking at elevation alone is not very useful, rather, the interaction of altitude and latitude and their influence on temperature is what matters.

This is the real reason why your barista is telling you about the elevation of the coffee you are about to drink.  The main reason that higher elevation coffee is more sought after is the taste. When well-cared for, high elevation coffee will produce the more acidic, aromatic and flavorful cup of coffee that we love, while lower elevation coffee tends to have a lower acidity with little character in the cup. Generally, a higher elevation coffee will be a better tasting coffee and by saying that the coffee was grown at 5,200’, it means the coffee should have a good flavor. Elevation is just one of dozens of factors that affect the taste of the coffee you are about to drink, but it is one of the most important ones. Feel free to ask your barista for more information about the coffee you’re about to drink and experiment with coffees from different elevations and regions of the world!

by Shawn Steiman Ph.d