Draft beer, otherwise known as draught beer, is a form of beer that has been minimally processed and served straight from a cask or keg. It comes from the English word "draught," which means "to pull from a cask with a pump."
Regular beer is fully pasteurized and filtered before it is bottled. Draft beer goes through no such process, and is served directly from the keg. It is still kept cold in order to preserve it.
Beer aficionados claim that the taste of draft beer is stronger and fresher, while bottled beer masks the flavor of the beer with the flavor of the bottle. The filtration process of regular beer also removes some of the aromatic compounds that naturally gives beer its flavor.
Draft beer is only available through a cask kegerator (a refrigerated keg) or from a bar, and is not sold in stores except in bulk. Draft beer often has active yeast still in it, and goes bad if not consumed during four to six weeks. Regular pasteurized beer keeps for several months.