The fluffy foam on your beer is being sabotaged by the very amino acids that are supposed to be its building blocks.
Brewers have long assumed that only certain types of amino acids were responsible for a flat, lifeless head on a beer. Almost all free amino acids, the leftovers when proteins break down, actively disrupt the stability of beer foam. These molecules act as tiny wedges that break the surface tension of the bubbles. Even if the good proteins are present, a high concentration of these free amino acids will still cause the foam to collapse. Brewers can now refine their fermentation process to minimize these waste products and ensure a perfect pour every time.
Free Amino Acids Decrease Beer Foam Stability
SSRN · 6632819
The assumption that “only basic amino acids damage beer foam” is incorrect and should be revised. Beer foam stability has long been discussed mainly in terms of foam-active proteins (e.g., LTP1 and Protein Z) and their loss or inactivation; however, our results demonstrate that foam can deteriorate through an additional and direct route: free amino acids themselves disrupt beer foam stability in the finished-beer matrix. In other words, foam deterioration is not explained only by a decrease in f