Coffee

      his article is about the beverage, which comes in many forms. For the seed from which it is made, see Coffee bean. For other uses, see Coffee (disambiguation).

Coffee

A cup of black coffee
Type	Hot or cold (usually hot)
Country of origin	Yemen
Introduced	Approx. 15th century (beverage)
Color	Dark brown, beige, black, light brown

Coffee is a brewed beverage prepared from the roasted seeds of several species of an evergreen shrub of the genus Coffea. The two most common sources of coffee beans are the highly regarded Coffea arabica, and the "robusta" form of the hardier Coffea canephora. The latter is resistant to the coffee leaf rust (Hemileia vastatrix), but has a more bitter taste. Coffee plants are cultivated in more than 70 countries, primarily in equatorial Latin America, Southeast Asia, and Africa. Once ripe, coffee "berries" are picked, processed, and dried to yield the seeds inside. The seeds are then roasted to varying degrees, depending on the desired flavor, before being ground and brewed to create coffee.

Coffee is slightly acidic (pH 5.0–5.1^[1]) and can have a stimulating effect on humans because of its caffeine content. It is one of the most popular drinks in the world.^[2]It can be prepared and presented in a variety of ways. The effect of coffee on human health has been a subject of many studies; however, results have varied in terms of coffee's relative benefit.^[3] The majority of recent research suggests that moderate coffee consumption is benign or mildly beneficial in healthy adults. However, coffee can worsen the symptoms of conditions such as anxiety, largely due to the caffeine and diterpenes it contains.^{[citation needed]  อ่านเพิ่มเติม...}