There’s an online beer aficionado we like to keep up with named Carolyn Smagalsi, a.k.a Beer Fox. Someone asked her the above question, and we thought we’d pass along the short/sweet scoop. It’s good to know, if you don’t already.
IBU stands for International Bittering Unit — the scale used to measure hop bitterness in beer. An IBU is one part per million of isohumulone, an acid derived from hops. If you like the very bitter “bite” of the “Extreme Beers,” a higher IBU would be an indication of that snap.
A General IBU Guide:
Ales
Pale Ale / Amber Ale – 20-50 IBU
India Pale Ale – 40-60 IBU (this would have quite a bitter bite)
ESB, aka Extra Special Bitters – 28-40 IBU
English Brown Ale – 20 IBU
Porter – 20-40 IBU
Irish Stout – 30-60 IBU (can be quite bitter, depending on signature)
Barleywine – 50-100 IBU (power punch!)
Lagers
American Pale Lager – 10-15 IBU
Pilsner – 25-45 IBU
Bock – 20-30 IBU