IBU 1
IBU 1 : An abbreviation for international bitterness (or bittering) unit, a unit used in brewing beer and ale. One IBU is equal to 1 part per million of isohumulone, an acid (derived from hops) that provides the bitterness in the brew. Measurements from 0 to about 70 IBU are possible, but most beers measure between 10 and 30 IBU