<P> A coffee bean is a seed of the coffee plant and the source for coffee . It is the pit inside the red or purple fruit often referred to as a cherry . Just like ordinary cherries, the coffee fruit is also a so - called stone fruit . Even though the coffee beans are seeds, they are referred to as "beans" because of their resemblance to true beans . The fruits--coffee cherries or coffee berries--most commonly contain two stones with their flat sides together . A small percentage of cherries contain a single seed, instead of the usual two . This is called a "peaberry". The peaberry occurs only between 10 and 15% of the time, and it is a fairly common (yet scientifically unproven) belief that they have more flavour than normal coffee beans . Like Brazil nuts (a seed) and white rice, coffee beans consist mostly of endosperm . </P> <P> The two most economically important varieties of coffee plant are the Arabica and the Robusta; ~ 60% of the coffee produced worldwide is Arabica and ~ 40% is Robusta . Arabica beans consist of 0.8--1.4% caffeine and Robusta beans consist of 1.7--4% caffeine . As coffee is one of the world's most widely consumed beverages, coffee beans are a major cash crop and an important export product, counting for over 50% of some developing nations' foreign exchange earnings . </P>

The trees producing the coffee bean were native to