简介:Coffee is a widely consumed beverage prepared from the roasted seeds—commonly called "beans"—of the coffee plant.
历史:Coffee was first consumed as early as the 9th century, when it was discovered in the highlands of Ethiopia.
From Ethiopia, it spread to Egypt and Yemen, and by the fifteenth 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.
种类: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 the 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 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 for political reasons.
In Europe it was once associated with rebellious political activities. Today, trade in coffee has a large economic value. Coffee is an important export commodity for many countries; in 2004, coffee was the top agricultural export for 12 countries, and in 2005, it was among the world's top fifteen legal agricultural exports in value.
From 1998 to 2000, 6.7 million tons of coffee were produced annually and forecasts predict that production will rise to 7 million metric tons annually by 2010.
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 consumed in excess.The current consensus of medical experts is that moderate coffee consumption is not a health concern.Coffee is also a source of caffeine, and the majority of all caffeine consumed worldwide comes from coffee.
参考资料：http://en.wikipedia.org/wiki/Coffee