The skin of the fruit is smooth, dense, and shiny, with a bitter aroma, while the flesh is very sweet, tender, and juicy, with mixed notes of watermelon, hibiscus, cherries, raspberries, and blueberries. In the center of the fruit are two blue-green seeds, which are the fresh form of coffee beans. Due to natural mutations, a small percentage of coffee berries will have a single berry inside, called "blueberries" and is said to produce sweeter and more flavorful coffee.
The coffee beans belong to the Rubiaceae family and belong to the genus Coffea. There are many different species of berry coffee plants, but two of the main commercially grown today are Coffea arabica, known simply as coffee arabica, and Coffea canephora, known as robusta coffee. There are over 100 varieties of arabica coffee, which account for most of the world's coffee production today. Robusta coffee has a higher caffeine content and more bitterness and is mainly used in blends or instant coffees. There is also a type of coffee known as the Luwak copy, supposed to be the most expensive coffee in the world. It is not a unique species but comes from a special method of harvesting coffee beans from the waste of the Asian palm civet cat, an animal native to South and Southeast Asia.