Decaffeination (decaf) is the removal of caffeine from coffee beans, cocoa, tea leaves and other caffeine-containing materials. While soft drinks which do not use caffeine as an ingredient are sometimes described as “decaffeinated”, they are better termed “uncaffeinated” because decaffeinated implies that there was caffeine present at one point in time. Decaffeinated drinks contain typically 1–2% of the original caffeine content, and sometimes as much as 20%. In the case of coffee, various methods can be used. The process is usually performed on unroasted (green) beans, and starts with steaming of the beans. They are then rinsed with a solvent that extracts the caffeine while leaving other constituents largely unaffected. The process is repeated from 8 to 12 times until the caffeine content meets the required standard (97% of caffeine removed according to the international standard, or 99.9% caffeine-free by mass as per the EU standard). Coffee contains over 400 components important to the taste and aroma of the drink, so it is difficult to remove the caffeine without affecting other components. Coffea arabica normally contains about half the caffeine of Coffea robusta. A Coffea arabica bean containing very little caffeine was discovered in Ethiopia in 2004.