Terroir - The effect of altitude on coffee and its taste

In this first part of the blog on The Terroir, I discuss the notion of altitude. I will talk about the effect of this attribute on the coffee as well as the effect on its taste.

Saturday afternoon, you enter a delicatessen, you see bags of coffee and, on the information written on them, there is the altitude. Do you really know what that means?

First of all, if this attribute is written on a bag of coffee, or mentioned on the coffee's description on the website, there is a better chance that this coffee is a specialty coffee. To find out, refer to my blog post here.

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We can categorize altitudes* as follows for coffee Arabica:

• 750m to 899m – low altitude
• 900m to 1199m – medium altitude
• 1200m to 1499m – high altitude
• 1500m and more – very high altitude

*Altitude in reference to MSL (mean sea level)

Coffee trees can grow lower than 750m, however it is often Robusta, where this botanical species is abundant, particularly in India and Vietnam.

In general, the more the coffee grows at high altitude, the greater the temperature differences will be between day and night, the lower the temperature will be in general, the more there will be a rarefaction of oxygen, and therefore, the ripening of the grains will take place more slowly, thus densifying the grain. This will also affect the physical appearance of the green grain. In addition, coffee trees at high altitudes are less vulnerable to disease, which increases their overall quality.

This slow maturation therefore gives them more complex sugars, unique tangy components, characterized by a prized flavor once roasted with care. Thus, the higher the elevation, the higher the acidity, distinctive taste and aromatic quality of the coffee.

However, this does not prevent coffee trees growing at lower altitudes from being less good, see the table below:

*It should be noted that the physical aspect of the green beans, the possible dominant notes and the natural acidity can be influenced by many other variables, in particular the microclimate, the botanical variety of the coffee plant and the drying processes grains

Some cases

• Take the case of Brazil. Coffee trees generally grow below 1200m in this country and their coffees are delicious. They may present chocolate notes with a mild nutty taste. Nevertheless, given the average altitude, it would not be possible to see distinct floral notes in a Brazilian coffee.
  
  
• In Ethiopia, the altitudes where coffee trees grow are generally very high, all above 1500m. With the different microclimates, drying techniques and ancestral botanical varieties of coffee trees, the coffees of Ethiopia offer an exceptional palette of tastes ranging from notes of jasmine flower, to the taste of blueberries or even literally full-bodied red wine.
  
  
• The exception of Kona, Hawaii. This American state is quite far from the equator and therefore, although it is very hot, the temperature quickly becomes cold at altitude. Thus, coffee can grow only at about 600m altitude on the island, because the temperatures are too cold beyond that. Based on the altitude alone, this would make it a fairly ordinary coffee, but the microclimate, composed of volcanic soil and ideal temperature, makes it a popular coffee.

And the context above all

So there are myriad possibilities. In particular, we must think about the notion of Latitude as well. Evaluating a cafe simply by its altitude is ill-advised, and it's my duty to help you better understand the context.

Coffee trees flourish at around 20° Celsius (68° F) and should not be exposed to excessively hot temperatures or risk of frost. This is why the coffee trees must grow at altitude to cause the beans to mature slowly, but not too high because there will be a risk of frost. This is where the notion of Latitude comes into play, because the closer we are to the equator, the more the heat remains at altitude and therefore, the more coffee can grow at very high altitudes.

Simply, places like southern Brazil or Hawaii are too far from the equator for coffee trees to have ideal temperatures at 1500m altitude. In addition, the topography of the land must be quite high in these places. On the contrary, in the region of Huila, Colombia, where this place is near the equator and the topography is very high, coffee trees can thrive at 2000m altitude.

As a result, an excellent coffee from Huila in Colombia will very often have fruity, tangy, even floral notes, while a good Brazilian in the south of the country will have comforting chocolate and nutty notes.

So you now understand that you have to evaluate the altitude not in isolation but rather according to the other attributes, in particular the region. Alas, this requires some knowledge of geography!

As a roaster, Colorès coffees are all selected after studying all the factors determining a specialty coffee: altitude, terroir, variety, origin, etc.

Viva Las Alturas.

Julian