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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 ''Brettanomyces'' 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, although Moulis et al. (2023) reported that for organisms that produced ETHP, there was always a 1:10 ratio between ETHP/ATHP or ETHP/APY, suggesting that this ratio might be governed by the chemistry of the media used and/or the [https://en.wikipedia.org/wiki/Reduction_potential reduction potential] <ref name="Moulis_2023" />. This was confirmed by second study by Moulis when ''B. bruxellensis'' was cofermented co-fermented or not cofermented co-fermented with APY-producing strains of ''Pediococcus paravulus'' <ref name="Moulis_2024">[https://oeno-one.eu/article/view/8060 Moulis, P., Miot-Sertier, C., Franc, C., Riquier, L., Beisert, B., Marchand, S., … Ballestra, P. (2024). Impact of Pediococcus parvulus and Saccharomyces cerevisiae on Brettanomyces bruxellensis mousy compound production. OENO One, 58(3). https://doi.org/10.20870/oeno-one.2024.58.3.8060]</ref>. Another unknown is why does ''Brettanomyces'' 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 ''Brettanomyces''. ====Co-fermentation with LAB====Moulis et al (2024) published a second study where they measured ATHP, ETHP, and APY produced by three ATHP/ETHP-producing strains of ''B. bruxellensis'' and three strains of APY-producing ''Pediococcus parvulus''. They measured levels of these three THP compounds when one of each ''B. bruxellensis'' was co-fermented with one each of the strains of ''P. parvulus''. They compared these levels to when each pair (one strain of ''B. bruxellensis'' and one strain of ''P. parvulus'') were fermented on their own, and then summed the total levels of each THP compound between the two separate fermentations. They found that APY levels, which was only produced by the ''P. parvulus' strains and not the ''B. bruxellensis'' strains, were much lower if the strains were co-fermented with any of the three strains of ''B. bruxellensis'. However, for ATHP and ETHP, 2 of the 3 strains of ''B. bruxellensis'' produced different levels of ATHP or ETHP when ''P. parvulus'' was co-fermented with them. The strain of ''P. parvulus'' also had an impact on this co-fermentation; some combinations of co-ferments produced more ATHP but less ETHP. The study concluded that the impact of co-fermentation inhibits APY produced by bacteria despite the strains used, and it can have an inhibitory or stimulatory impact on ATHP/ETHP, depending on the combinations of strains. The authors suggested several possible explanations <ref name="Moulis_2024" />: <blockquote>Previous results (Strickland et al., 2016) showed that less 4-ethylphenol (EP), a compound contributing to the “Brett character” in wine, was produced when ''P. parvulus'' and ''B. bruxellensis'' were jointly inoculated rather than separately. Here, ''P. parvulu''s and ''B. bruxellensis'' produce more ATHP and no APY at all when they are together. There are several hypotheses to explain that. First, Moulis (Moulis, 2023), proposed that ATHP production could correspond to a signal or a response to a signal between the different cells of ''B. bruxellensis'', to respond to stress. Here, ''B. bruxellensis'' could reply to the stress of the presence of ''P. parvulus'' by ATHP over-production. ''P. parvulus'' could thus directly influence the metabolism of ''B. bruxellensis'', resulting in the production of more ATHP than 4-ethylphenol in its presence. A second hypothesis is that ''B. bruxellensis'' could change the balance of acylation by ''P. parvulus''. Costello and Henschke (2002) proposed a formation pathway for APY and ATHP by LAB from ornithine and lysine, respectively. This formation pathway, in both cases, ends up with acylation (of piperideine for ATHP and of pyrroline for APY). ''B. bruxellensis'' could inhibit APY production either by inhibiting the pathway or by preferentially inducing ATHP acylation by ''P. parvulus''. Moreover, one of the production routes proposed by Grbin et al. (2007) involves cadaverine as a biosynthetic intermediate. Lactic acid bacteria such as ''O. oeni'' or ''P. parvulus'' are known to produce large quantities of biogenic amines (Granchi et al., 2005; Wade et al., 2019) and they can biosynthesise cadaverine to be metabolised by ''B. bruxellensis''. It would be interesting to explore these hypotheses in a future study <ref name="Moulis_2024" />.</blockquote> Moulis et al (2024) also attempted to study the effects of co-fermenting ''B. bruxellensis'' with ''Saccharomyces cerevisiae''; however, the definitive results were not presented due to a technical issue with the equipment used to measure THP compounds. Nonetheless, the authors suggested that ATHP and ETHP appeared to be higher when ''B. bruxellensis'' was co-fermented with ''S. cerevisiae'' versus when fermented on its own. The authors hypothesized that this could be due to more acetaldehyde production by ''S. cerevisiae'', which has been identified as a precursor to ATHP production. Another possibility would be nutrients released from less produced by ''S. cerevisiae'' <ref name="Moulis_2024" />.