Bitterness Units (BU)
Same as International Bitterness Units (IBU).
The measure of the bittering substances in beer (analytically assessed as milligrams of isomerized alpha acid per liter of beer, in ppm). This measurement depends on the style of beer. Light lagers typically have an IBU rating between 5-10 while big, bitter India Pale Ales can often have an IBU rating between 50 and 70.
By Justin Beerber on Mar. 23, 2016