The coffee plant is the source of coffee, from which we extract our precious beans to then roast and infuse them, however we like or however we enjoy them best.
It is a shrub of the Rubiaceae family that in the wild can reach up to ten meters in height, although in cultivation and through pruning it is kept at a height of between three and five meters to facilitate the harvesting of its fruit. It flowers for the first time from the third or fourth year of its life. More than four hundred different varieties are recognized among the main ones and subspecies, but to begin with we are going to look at the differences between two of the most consumed species in the world, in order to distinguish what each one of them brings to the final cup.
Arabica and Robusta coffee
The coffees we find on the market come mainly from two varieties of coffee plant that are considered the main ones. On one hand we have Arabica varieties , and on the other hand, Robusta varieties , or more technically known as Canephora . There are many differences between the two, from their structure to the fruit they produce. One of the most important differences lies in the caffeine content. The Robusta coffee plant contains three to four times more caffeine in its sap than the Arabica variety, which it uses to protect itself from external attacks such as insect pests, diseases, and water stress. Therefore, as you are probably guessing, the Arabica variety is much more likely to die due to its lower caffeine content, and so:
How do farmers manage to keep it alive?
It's quite simple: they plant their coffee at higher altitudes. The higher the altitude, the scarcer the oxygen, therefore fewer external threats can survive and attack the coffee plant. For this reason, the Arabica variety can only survive if cultivated at a minimum altitude of 600 or 800 meters above sea level. I know what you're thinking, that the smart thing to do is to grow robusta, since it withstands better and we run less risk, well no.
Arabica coffee is of higher quality
The Robusta coffee plant, due to its high caffeine and chlorogenic acid content, imparts an excessive and unpleasant bitterness to the final cup, leaving it devoid of flavor complexity, with virtually no acidity and an intense woody note. Therefore, after drinking the coffee, we are left with an intense and unpleasant aftertaste that lingers in the throat and needs to be quickly rinsed away with a little water. This does not happen with the coffee provided by the Arabica variety, since its lower caffeine and chlorogenic acid content significantly reduces bitterness in the cup. This, along with the effects of growing at higher altitudes, such as reduced oxygen levels, results in a much slower ripening of the fruit, producing a coffee bean that is significantly denser than Robusta, with higher sugar content. This translates to a smoother flavor in the cup, with little to no bitterness, fruity or floral notes, and a long, pleasant aftertaste. In short: a much more complex and full flavor than robusta. 
Is Arabica coffee more expensive?
Economically, Robusta is a much cheaper coffee plant to grow because it is easier for it to survive. It's also cheaper to harvest, as it can be grown at lower altitudes, making it easier than in steep mountains. It's also cheaper to transport since it can be grown near ports for easier shipping, and it typically yields two or three harvests a year. Arabica, on the other hand, only produces one or two harvests annually. But not everything translates to the price per kilo of coffee; if we divide it by the cup, the Arabica variety also has something to say, since being much denser we always end up getting more cups per kilo with Arabica coffee than with Robusta. Even so, a cup of good Arabica coffee will always be a few cents more expensive than Robusta, but isn't it worth a few cents for a pleasant cup that makes us want more? Finally, another fact: almost 70% of the coffee consumed worldwide comes from the Arabica variety. Makes you think, doesn't it? There must be a reason.
