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A study <ref name="Tyrawa_2017">[https://www.facebook.com/groups/MilkTheFunk/permalink/1285391951489016/ "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. Tyrawa also showed that there are higher levels of esters in 100% ''Brettanomyces'' fermentations compared to when ''Brettanomyces'' is co-fermented with ''S. cerevisiae'' (see [[Brettanomyces_and_Saccharomyces_Co-fermentation#Review_of_Scientific_Analysis_2|''Brettanomyces'' and ''Saccharomyces'' Co-fermentation]]. A somewhat speculative conclusion of this might be that the high ester levels of 100% ''Brettanomyces'' fermented beers might mask the "funky" flavor characteristics of phenols (4-ethylguaiacol, 4-ethylphenol, etc). 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-ethylphenol and 4-ethylguaiacol 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>, however, Tyrawa's data looked at phenol levels over time and found that initially phenol levels were higher in 100% ''Brettanomyces'' fermentations compared to co-pitched with ''S. cerevisiae'' but over time the phenol levels in the co-pitch were slightly higher and phenol levels in general fluctuated quite a bit over the entire 21 day trial <ref name="Tyrawa_Masters">[https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14757 Demystifying Brettanomyces bruxellensis: Fermentation kinetics, flavour compound production, and nutrient requirements during wort fermentation. University of Guelph, Masters Thesis. Department of Molecular and Cellular Biology. 2020.]</ref>.
[https://ir.library.oregonstate.edu/downloads/gh93h631p Riley Humbert's Bachelors thesis] reported that after a 30-35 day primary versus secondary fermentation with different strains of ''B. bruxellensis'', the primary fermentations tended to produce a wider spread of phenols based on strain but overall produced less phenols than when the same strains were fermented in secondary after a primary fermentation with London Ale III. Humbert speculated that perhaps the ''Brettanomyces'' might have had a head start on converting 4-vinyl phenols to 4-ethyl phenols due to the production of 4VG by ''Saccharomyces'', implying that maybe phenol concentrations would have matched that of the primary fermentation trials if the beers were aged longer <ref>[https://ir.library.oregonstate.edu/downloads/gh93h631 gh93h631p Riley Humbert for the degree of Honors Baccalaureate of Science in Chemical Engineering presented on May 21, 2021. Title: Performance of Brettanomyces Yeast Strains in Primary and Secondary Beer Fermentations.]</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" />. 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>.