A cup of coffeeType: Hot or cold (usually hot)Country of origin: Yemen, EthiopiaIntroduced: Approx. 15th centuryColour: Dark brown, beige, light brown, blackCoffee is a brewed drink prepared from roasted coffee beans, which are the seeds of berries from the Coffea plant. The genus Coffea is native to tropical Africa (specifically having its origin in Ethiopia and Sudan) and Madagascar, the Comoros, Mauritius, and Réunion in the Indian Ocean.The plant was exported from Africa to countries around the world and coffee plants are now cultivated in over 70 countries, primarily in the equatorial regions of the Americas, Southeast Asia, India, and Africa. The two most commonly grown are the highly regarded arabica, and the less sophisticated but stronger and more hardy robusta. Once ripe, coffee berries are picked, processed, and dried. Dried coffee seeds (referred to as beans) are roasted to varying degrees, depending on the desired flavor. Roasted beans are ground and brewed with near-boiling water to produce coffee as a beverage.Coffee is slightly acidic and can have a stimulating effect on humans because of its caffeine content. Coffee is one of the most popular drinks in the world. It can be prepared and presented in a variety of ways (e.g., espresso, French press, cafe latte, etc.). It is usually served hot, although iced coffee is also served. Clinical studies indicate that moderate coffee consumption is benign or mildly beneficial in healthy adults, with continuing research on whether long-term consumption inhibits cognitive decline during aging or lowers the risk of some forms of cancer.The earliest credible evidence of coffee-drinking appears in the middle of the 15th century in the Sufi shrines of Yemen. It was here in Arabia that coffee seeds were first roasted and brewed in a similar way to how it is now prepared. Coffee seeds were first exported from East Africa to Yemen, as the coffea arabica plant is thought to have been indigenous to the former.Yemeni traders took coffee back to their homeland and began to cultivate the seed. By the 16th century, it had reached Persia, Turkey, and North Africa. From there, it spread to Europe and the rest of the world.Coffee is a major export commodity: it is the top agricultural export for numerous countries and is among the world's largest legal agricultural exports.It is one of the most valuable commodities exported by developing countries. Green (unroasted) coffee is one of the most traded agricultural commodities in the world. Some controversy is associated with coffee cultivation and the way developed countries trade with developing nations and the impact of its cultivation on the environment, in regards to clearing of land for coffee-growing and water use. Consequently, the markets for fair trade coffee and organic coffee are expanding.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.The two most economically important varieties of coffee plant are the Arabica and the Robusta; 75–80% of the coffee produced worldwide is Arabica and 20% 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.