There are four types of coffee beans : Arabica (Coffee arabica), Robusta (Coffee caniphora), Liberica (Coffee liberica), and Excelsa (Coffee liberica var. dewevrei). Each with different characteristics and taste profiles, and different requirements for cultivation.
ARABICA
Arabica is the most well known of the types of coffee beans, it accounts for 60 – 70 percent of all the coffee produced worldwide. Arabica is cultivated in mountains with more than 1,000 meters above sea level, and where rain is plentiful. These beans have sweeter, lighter and smoother flavor that most coffee drinkers prefer. It has an acidity that balances out the bitterness in coffee. The beans are more oval in shape and flat, and have more oil in the than the other types of beans.
robusta
Robusta makes up less than 40 percent of all the coffee produced worldwide and is grown mostly in Asian coffee-producing countries. Robusta trees can grow even in lower elevation, and produces greater yields. Less care and attention needs to be taken with robusta trees so farmers are most likely to plant robusta instead of arabica. It has twice the caffeine of all the other coffee varieties and tend to have earthy, smokey, and woody overtones. Robusta beans are perfect for espresso, because of its bitter taste and the thick crema that comes out of the beans, that espresso lovers are looking for. Robusta beans are smaller and have a more circular shape than all the other coffee bean types.
liberica
Liberica coffee is rare, it accounts for only 2% of the coffee produced worldwide. It is grown mostly in Southeast Asia, particularly in Malaysia, Indonesia and the Philippines. These beans have an almond shape with an exceptional aroma, very strong flavor, with some people saying that you either “love or hate it, with no in between.” A lot of people would describe it as bitter, smokey with spicy notes, while some would taste notes of blueberries. It is mostly used for espresso, cold brews, or what they call Kopi in Malaysia and Singapore where they mix it with sweetened milk.
EXCELSA
Excelsa was recently re-classified as a variety of Liberica, because the plants are similar. The beans have a distinctive teardrop shape, similar to to Liberica, but the size is much much smaller. The coffee itself is also so different from Liberica so they still seem to be an entirely separate specie. Excelsa accounts for 6% of world coffee production and cultivated mainly in Southeast Asia. It is described to have a distinctive tart, fruity, dark, mysterious taste and is used mostly in house blends to add extra thickness and flavor.