What are alpha acids commonly referred to in brewing?

Alpha acids, which are a critical component in hops used for brewing, are commonly referred to as humulones. These compounds are primarily responsible for the bitterness in beer, which is essential for balancing the sweetness of the malt. During the brewing process, alpha acids undergo a thermal isomerization when boiled, converting into iso-alpha acids, which are actually the bitter compounds perceived in the finished beer.

While lupulones, iso-alpha acids, and polyphenols are related to hops and the brewing process, they refer to different aspects. Lupulones are another group of acids found in hops but are distinct from alpha acids. Iso-alpha acids specifically refer to the forms of alpha acids that provide bitterness after boiling, but the term does not encompass the initial compounds themselves. Polyphenols, on the other hand, are a group of compounds primarily associated with flavor and mouthfeel rather than bitterness.

Understanding that humulones are the alpha acids in hops helps clarify their role in contributing to the overall flavor profile and bitterness of beer.