The two most commercially used species worldwide are Coffea arabica and Coffea canephora (robusta), each unique in many ways. Commercially, arabica comprises about 70% of varietals with the remaining 30% belonging to the (canephora) robusta variety. The differences between the two species, commercially, rely on the caffeine and flavor content. C. canephora (robusta) is a heavily caffeinated bean, but due to its high caffeine content it is also more bitter to the palate while C. arabica tends to be sweeter with slightly less caffeine.