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A study <ref name="Tyrawa_2017">[https://www.facebook.com/groups/MilkTheFunk/1285391944822350/ "Funky can be Great: Brettanomyces bruxellensis Beer Fermentations" (poster for study). Caroline Tyrawa, Richard Preiss, and George van der Merwe. 2017.] </ref> conducted by Caroline Tyrawa and Richard Preiss measured, among other things, the 4-ethyl guaiacol in 100% ''Brettanomyces bruxellensis''. It shows significant levels of 4-ethyl guaiacol in wort fermented by various strains of the before-mentioned yeast. A somewhat speculative conclusion of this might be that the high ester levels of 100% ''Brettanomyces'' fermented beers might mask the funk (4-ethyl guaiacol, 4-ethyl phenol, etc) produced. As esters tend to be chemically unstable (ref?) the fruity character of a ''Brettanomyces'' beer will fade over time allowing the funk a more prominent role. This is also supported by a study that looked at 4-ethyl phenol and 4-ethyl guiacol levels in one strain of ''B. bruxellensis'' when fermented alone and when co-fermented with a wine strain (EC1118); they found that there were about 20% more phenols in the 100% ''B. bruxellensis'' fermentation than there were when the ''B. bruxellensis'' was co-fermented with EC1118 (this might have been because the wine strain uesd, EC1118, can metabolize hydrocinnamic precursors differently and reduce the 4-vinyl levels <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1770814702946736/ Richard Preiss. Statements about the Kosel et al. study. Milk The Funk Facebook gruop. 07/26/2017.]</ref>) <ref>[https://academic.oup.com/femsyr/article-abstract/17/4/fox018/3867021/The-influence-of-Dekkera-bruxellensis-on-the?redirectedFrom=fulltext The influence of Dekkera bruxellensis on the transcriptome of Saccharomyces cerevisiae and on the aromatic profile of synthetic wine must. Janez Kose, Neža Čade, Dorit Schulle, Laura Carret, Ricardo Franco-Duarte Peter Raspor. 2017.]</ref>.
Thomas Hübbe's masters thesis also supports the hypothesis that ''Brettanomyces'' produces more esters other than ethyl acetate when it is not co-fermented with ''S. cerevisiae'', specifically because it has better growth without competition from ''S. cerevisiae''. Although below threshold, the esters ethyl caprylate, ethyl caprate, ethyl dodecanoate, and ethyl tetradecanoate were significantly lower when ''Brettanomyces'' was co-fermented with ''S. cerevisiae'' and ''Lactobacillus'' than when it was fermented with only ''Lactobacillus''. Ethyl acetate (still under threshold levels) was higher when ''Brettanomyces'' was fermented with ''Lactobacillus'' but without ''S. cerevisiae'', and significantly higher when it was fermented with both ''Lactobacillus'' and ''S. cerevisiae'' <ref name="Hubbe">[https://www.facebook.com/groups/MilkTheFunk/1407620505932826/ Effect of mixed cultures on microbiological development in Berliner Weisse (master thesis). Thomas Hübbe. 2016.]</ref>. This seems to support the idea that, with the exception of the ester ethyl acetate, 100% Brettanomyces fermentations are not necessarily less phenolic, but that they are more fruity probably due to higher growth without competition from ''S. cerevisiae'' (although phenols were not measured in Hübbe's study) <ref>[https://www.facebook.com/groups/MilkTheFunk/1407620505932826/?comment_id=1407723619255848&comment_tracking=%7B%22tn%22%3A%22R8%22%7D Comments by Richard Preiss regarding Thomas Hübbe's masters thesis. 09/15/2016.]</ref>.
==See Also==