How Coffee Works

Coffee has two main varieties: arabica and robusta. Arabica is descended from the original Ethiopian coffee trees. The coffee made from this variety is mild and aromatic. It's the king of coffee and accounts for about 70 percent of the world's coffee production. These coffee trees grow best in higher altitudes, between 2,000 and 6,000 feet (610 and 1,829 m) above sea level. Mild temperatures (60 to 75 degrees Fahrenheit / 16 to 24 degrees Celsius) and about 60 inches (152 cm) of rain per year ensure arabica's growth. Heavy frost will kill arabica coffee trees.

Robusta coffee trees represent about 30 percent of the world's market. The bean is smaller and rounder than an arabica bean. Robusta is a heartier plant and can withstand warmer temperatures, up to 85 F (29 C). It can also thrive at lower altitudes than arabica. Robusta beans produce a bitter-tasting coffee with about 50 percent more caffeine than arabica. You'll find robusta coffee trees in Southeast Asia and Brazil.

Coffee connoisseurs discuss beans like wine lovers discuss various vintages. Beans from trees grown in Africa and Arabia are characterized as "complex, with intense berry or spice undertones." Coffee from Latin America is described as "clean-tasting, tangy and bright." Southeast Asian coffees are typically "full-bodied and earthy."

Many coffees are blends of several types of coffee, which produces a more complex flavor.