Coffee is a widely consumed beverage prepared from the roasted seeds—commonly called "beans"—of the coffee plant. Coffee was first consumed as early as the 9th century, when it appeared in the highlands of Ethiopia.From Ethiopia, it spread to Egypt and Yemen, and by the 15th century had reached Persia, Turkey, and northern Africa. From the Muslim world, coffee spread to Italy, then to the rest of Europe and the Americas.Today, coffee is one of the most popular beverages worldwide.
The two most commonly grown species of the coffee plant are Coffea canephora and C. arabica, which are cultivated in Latin America, Southeast Asia, and Africa. Coffee berries are picked, processed, and dried. The seeds are roasted at temperatures around 200 °C (392 °F), during which the sugars in the bean caramelize, the bean changes color, and flavor develops. The beans are roasted to a light, medium, or dark brown color, depending on the desired flavor.The roasted beans are ground and brewed in order to create the beverage coffee.
Coffee has played an important role in many societies throughout history. In Africa and Yemen, it was used in religious ceremonies. In the 17th century, it was banned in Ottoman Turkey. In Europe, it was once associated with rebellious political activities. Today, trade in coffee has a large economic value. Coffee is one of the world's more important primary commodities; in 2003, coffee was the world's sixth-largest legal agricultural export in value. From 1998 to 2000, 6.7 million tons of coffee were produced annually, and it is predicted that by 2010 production will rise to 7 million tons annually. Among coffee drinkers the average coffee consumption in the United States is 3.1 cups of coffee per day.
The health effects of coffee are disputed, and many studies have examined the relationship between coffee consumption and certain medical conditions. Studies have suggested that the consumption of coffee lowers the risk of certain diseases but may have negative effects as well, especially when excessive.
