Coffee is a brewed beverage with a distinct aroma and flavor, prepared from the roasted seeds of the Coffea plant.
The seeds are found in coffee "cherries", which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia, India and Africa. Green (unroasted) coffee is one of the most traded agricultural commodities in the world. Coffee is slightly acidic (pH 5.0Ц5.1) and can have a stimulating effect on humans because of its caffeine content. It is one of the most consumed drinks in the world. An important export commodity, coffee was the top agricultural export for twelve countries in 2004, and it was the world's seventh-largest legal agricultural export by value in 2005. Some controversy is associated with coffee cultivation and its impact on the environment. Consequently, organic coffee is an expanding market.
Many studies have examined the health effects of coffee, and whether the overall effects of coffee consumption are positive or negative has been widely disputed. 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 some conditions, largely due to the caffeine and diterpenes i contains.
Ethiopian ancestors of today's Oromo people were believed to have been the first to recognize the energizing effect of the coffee plant, though no direct evidence has been found indicating where in Africa coffee grew or who among the natives might have used it as a stimulant or even known about it, earlier than the 17th century. The story of Kaldi, the 9th-century Ethiopian goatherder who discovered coffee, did not appear in writing until 1671 and is probably apocryphal. Other accounts attribute the discovery of coffee to Sheik Omar. According to the ancient chronicle (preserved in the Abd-Al-Kadir manuscript), Omar, who was known for his ability to cure the sick through prayer, was once exiled from Mocha, Yemen to a desert cave near Ousab. Starving, Omar chewed berries from nearby shrubbery, but found them to be bitter. He tried roasting the seeds to improve the flavor, but they became hard. He then tried boiling them to soften the seed, which resulted in a fragrant brown liquid. Upon drinking the liquid Omar was revitalized and sustained for days. As stories of this "miracle drug" reached Mocha, Omar was asked to return and was made a saint. From Ethiopia, the beverage was introduced into the Arab world through Egypt and Yemen