Changes

The production of ATHP is not efficient, meaning that the amount of ATHP produced is not proportional to the amount of L-lysine consumed. Therefore, the production of ATHP appears to be a byproduct (secondary metabolite) of L-lysine catabolism <ref name="Snowdon"></ref>. ATHP is further metabolized into ETHP by ''Brettanomyces'', although not much is known about this metabolic process <ref>[http://ucce.ucdavis.edu/files/repositoryfiles/Joseph_5_Aromatic_Diverswity_of_Brettanomyces-82350.ppt Joseph, C.M. Lucy. ''Aromatic Diversity of Brettanomyces''. U.C. Davis. Retrieved 3/10/2015.]</ref><ref name="Snowdon"></ref>. ETHP has a significantly higher taste threshold, and is often not detected in contaminated wine <ref name="Oelofse"></ref>.

The presence of the "mousy off-flavor" caused by forms of THP appears to be temporary in beer. Although not much is known about the degradation or metabolic breakdown of ATHP/ETHP, it tends to age out of beer after 2-6 months. Since the odor/taste threshold for ETHP is much higher than ATHP, and ATHP appears to be metabolized into ETHP by ''Brett'' over time, this may be one of the mechanisms by which the mousy off-flavor ages out of beer. The possibility of ETHP breakdown is not mentioned in any studies that we know of. Another unknown is why does ''Brett'' produce ATHP shortly after kegging and force carbonating a beer that has reached final gravity. The most likely cause is oxygen pick up during the kegging process. Pitching fresh ''Saccharomyces'' at bottling/kegging time and naturally carbonating the beer with sugar has reportedly reduced mousy off-flavor detection, perhaps because ''Saccharomyces'' metabolizes both the oxygen and sugar faster than ''Brett''.