The coffee tree is an evergreen shrub, which in the wild can grow up to 30 feet high, but is kept trimmed to 6-9 feet to facilitate harvesting. There are two commercially significant coffee species—Coffea Arabica and Coffea Robusta.
Plants produce coffee cherries, which usually contain two half beans or one bean called peaberry. Arabica cherries are oblong, while those of Robusta are round.
All high-quality coffee comes from Arabica trees. The ideal elevation for arabica growth is 500-6000 feet above sea level, where average temperatures are below 75 degrees. The cooler the temperatures, higher elevation, the slower the growth which results in a higher bean density and flavor. Because of it's superior quality and taste, and higher cultivation costs, arabica is more expensive than robusta.
The tougher robusta bean variety yields greater volumes of coffee per growing area, is more resistant to disease and tolerates higher temperatures, making it easier and cheaper to cultivate. This bean grows best in humid, tropical climates and altitudes between sea level and 3200 feet. Robusta beans have less flavor, and a higher caffine content than arabica beans, and are a large ingredient in commercial coffees.
