Coffee is a natural product grown in tropical countries. There are three main varieties of coffee plants - Coffea arabica, Coffea canephora, and Coffea liberica. Coffee beans are processed using dry or wet methods and then roasted. There are various methods for preparing coffee including drip, French press, espresso, and Turkish coffee. Specialty coffees may include additions like alcohol. The most expensive coffee is kopi luwak which is made from coffee beans that have passed through the digestive tract of the Asian palm civet.