What is ibu in beer?

IBU in Beer: Understanding Bitterness

IBU stands for International Bitterness Units. It's a scale used to measure the perceived bitterness of beer, which primarily comes from the alpha acids found in hops.

Here's a breakdown:

• Measurement: IBU is a scientific measurement of the iso-alpha acids in the beer, specifically measured in parts per million (ppm).
• Perception: While IBU measures the quantity of bitter compounds, perceived bitterness can be influenced by other factors such as malt sweetness, alcohol content, and other ingredients. A beer with a high IBU but also a high residual sugar content might not taste as bitter as a beer with the same IBU but less sweetness.
• Range: The IBU scale generally ranges from 0 to 100+, although most beers fall between 5 and 70 IBU. Some extremely hoppy beers can exceed 100 IBU, but the human palate has difficulty distinguishing differences above that level.
• Style Dependence: Different beer styles have different expected IBU ranges. For example, a light lager might have an IBU of 8-12, while a double IPA could have an IBU of 60-100+.
• Factors Influencing IBU: The final IBU of a beer is affected by factors such as the variety of hops used, the amount of hops used, when the hops are added during the boil (earlier additions contribute more bitterness), and the length of the boil.
• Not Absolute: It's important to note that IBU is just one factor in determining the overall flavor profile of a beer. It provides an indication of bitterness but doesn't tell the whole story.