What happens to beta acids during fermentation?

During fermentation, beta acids do indeed contribute bitterness to the beer, but their behavior is quite distinct from alpha acids. It's important to recognize that beta acids are less soluble in beer and are not as effective at imparting bitterness compared to alpha acids. However, they do play a role in the overall flavor profile and can contribute to perceived bitterness when combined with other compounds in the beer.

Alpha acids are primarily responsible for the bitterness in finished beers, but beta acids, while not as influential, still can have an impact, especially in certain beer styles where their presence enhances the complexity of the flavor profile. As fermentation progresses, beta acids do not undergo isomerization, which is a process that occurs primarily with alpha acids, resulting in the formation of iso-alpha acids that provide bitterness.

The other options do not align with the known behavior of beta acids during fermentation. They do not increase in concentration nor stabilize foam like proteins do, and misunderstanding their role can lead to misconceptions about beer bitterness. Therefore, acknowledging that beta acids contribute to the overall perception of bitterness, despite being less impactful than alpha acids, clarifies their role within the fermentation process.