Arabica vs. Robusta
Coffea arabica and Coffea canephora -- known to us, simply, as arabica and robusta. What’s the difference between arabica and robusta? What accounts for the chasm between our two most predominant coffee varieties?
Robusta. As the name implies, these plants are very hearty, resistant to disease, and grow in lower altitudes. These traits propelled commercial popularity into convenience stores, diners and instant coffee packets worldwide. While robusta coffee once accounted for about 70% of the global coffee supply (remember your grandmother’s large red cans?), they now account for something like 40% (arabica essentially making up the rest).
In the cup, however, the heavy body and low acid nature of robusta coffees have rendered it (more recently) the industry’s black sheep. Known for its body and low acid, it can take a lot of effort to find robustas that don’t present the gritty wood and burnt rubber that typifies these coffees. But clean robustas do exist and have long been popular in Italian espresso blends where they don’t have quite the same reputation as they do in the U.S.
Arabica. In the other corner, arabica is coffee’s trust fund baby. For those keeping track, it is the genetic cross between Coffea canephora (robusta) and Coffea eugenioides, making it (gasp!) a literal child of robusta. Arabica presents qualities of both of its genetic ancestors to produce a relatively easy-to-grow, disease resistant plant (traits of robusta) with unique sweetness and mild acidity (traits of C. eugenioides).
The result is a highly nuanced bean with a mild body, slight acidity and less caffeine (about half that of robusta), but with more sugars and thus more flavor.
Equally important, though, is it’s resilience and ability to grow at high altitudes.
Why does elevation matter? As we’ve discussed before, cooler and more mild environmental conditions that exist at higher altitudes allow coffee beans to mature more slowly, thus allowing the beans to develop more nuanced characteristics. Many times, these high altitude coffees are grown across volcanic mountain ranges, where biodiversity and extremely fertile soil gives rise to stellar coffees.
Though, it should be noted that elevation and global region both matter. Coffee grows mostly in the tropics; that belt of our globe bordered by 23.5° North and 23.5° South latitude (Mill “47”… hint, hint), where rain is plentiful and weather is warmer and more moderate. Not all high altitude places in the world are suitable for coffee cultivation. If it’s too cold, coffee plants will die or simply not produce fruit. High elevation, when taken at face value, is not always an indicator of great coffee.
Plant Genetics and the Future of Coffee. An emerging worry amongst some scientists is that because arabica is so widespread, and has such little genetic variation, it could be significantly threatened by one new disease, insect or… climate change (!).
We have talked about the many cultivars around the world (both natural hybrids and selective breeding) that are in play to mitigate these threats, but perhaps the most promising “rediscovery” was just announced in April: a long-lost variety, Coffea stenophylla, was found in West Africa. Its most promising attribute other than good taste? It can tolerate a warmer growing temperature than even robusta!