What does IBU stand for?

• A. International Beer Unit
• B. Isobaric Buoy Unit
• C. International Bitterness Unit
• D. Ingredient Balance Unit

Answer: (C)

IBU is a standard for measuring beer bitterness. It stands for International Bitterness Unit and reflects the concentration of bittering compounds, mainly iso-alpha acids, in the beer. The higher the IBU, the more bitterness is present, although how bitter a beer tastes also depends on malt sweetness and other factors, so the number isn’t a perfect predictor of perceived bitterness. A common way to remember it is that 1 IBU roughly equals 1 mg of iso-alpha acids per liter. The other terms don’t fit because they describe unrelated concepts or fictitious units.