Editing Pellicle
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Pellicles can be formed by a variety of wild yeast and bacteria.<ref name="MTF-pellicle"/> Therefore it is not possible to identify which microbes(s) may be present based solely on the appearance of the pellicle or its characteristics — microbiological testing must be performed for identification.<ref>Widmayer C. [https://www.facebook.com/groups/MilkTheFunk/permalink/3292440674117457/ Comments from a professional fermentation/yeast researcher.] Milk the Funk Facebook group. Feb 2020.</ref> | Pellicles can be formed by a variety of wild yeast and bacteria.<ref name="MTF-pellicle"/> Therefore it is not possible to identify which microbes(s) may be present based solely on the appearance of the pellicle or its characteristics — microbiological testing must be performed for identification.<ref>Widmayer C. [https://www.facebook.com/groups/MilkTheFunk/permalink/3292440674117457/ Comments from a professional fermentation/yeast researcher.] Milk the Funk Facebook group. Feb 2020.</ref> | ||
Since commercial strains of [[brewers yeast]] used for [[beer]] and [[wine]] do not form a pellicle (except for [[sherry]]/flor yeast<ref>Eldarov MA, Beletsky AV, Tanashchuk TN, Kishkovskaya SA, Ravin NV, Mardanov AV. [https://www.frontiersin.org/articles/10.3389/fmicb.2018.00965/full Whole-genome analysis of three yeast strains used for production of sherry-like wines revealed genetic traits specific to flor yeasts.] ''Front Microbiol.'' 2018;9(965).</ref><ref>Van Mulders SE, Ghequire M, Daenen L, Verbelen PJ, Verstrepen KJ, Delvaux FR. [https://lirias.kuleuven.be/retrieve/129510 Flocculation gene variability in industrial brewer’s yeast strains.] ''Appl Microbiol Biotechnol.'' 2010;88:1321–1331.</ref> and possibly WLP644<ref>[https://www.whitelabs.com/sites/default/files/644_Explanation.pdf 644 Explanation.] White Labs. Accessed April 2020.</ref>), | Since commercial strains of [[brewers yeast]] used for [[beer]] and [[wine]] do not form a pellicle (except for [[sherry]]/flor yeast<ref>Eldarov MA, Beletsky AV, Tanashchuk TN, Kishkovskaya SA, Ravin NV, Mardanov AV. [https://www.frontiersin.org/articles/10.3389/fmicb.2018.00965/full Whole-genome analysis of three yeast strains used for production of sherry-like wines revealed genetic traits specific to flor yeasts.] ''Front Microbiol.'' 2018;9(965).</ref><ref>Van Mulders SE, Ghequire M, Daenen L, Verbelen PJ, Verstrepen KJ, Delvaux FR. [https://lirias.kuleuven.be/retrieve/129510 Flocculation gene variability in industrial brewer’s yeast strains.] ''Appl Microbiol Biotechnol.'' 2010;88:1321–1331.</ref> and possibly WLP644<ref>[https://www.whitelabs.com/sites/default/files/644_Explanation.pdf 644 Explanation.] White Labs. Accessed April 2020.</ref>), it can be an indisputable sign of contamination.<ref name="Humbard"/> (See [[Contamination]] for more info.) | ||
On the other hand, pellicle formation is normal for fermentations that contain wild microbes or non- | On the other hand, pellicle formation is normal for fermentations that contain wild microbes or non-Saccharomyces cultures such as [[Brettanomyces]].<ref>[https://www.homebrewtalk.com/forum/threads/pellicle-photo-collection.174033/ Pellicle photo collection.] HomebrewTalk forum. 2010.</ref> For example, a pellicle frequently forms in [[sour beer|mixed-fermentation beers]] or wines/ciders/meads with Brettanomyces or unpasteurized fruit or honey, and pellicle formation is a hallmark of [[kombucha]] and [[vinegar]] production. The appearance of a pellicle in these products doesn't reflect what may be happening in the fermentation with regard to quality or progress, it merely indicates the presence of the microbes.<ref name="Humbard"/> In wine, adequate pH-adjusted [[sulfite]] levels post-fermentation can inhibit these microbes and therefore prevent the formation of a pellicle. | ||
"Kahm yeast" is a colloquial term for a pellicle,<ref>Colleen. [https://fermentools.com/what-is-kahm-yeast-is-it-safe/ What is kahm yeast & is it safe?] Fermentools. 2018.</ref> and it is a misnomer because it is not always created by yeast. Similarly, the pellicle on [[kombucha]] is often mistakenly called the "SCOBY". | "Kahm yeast" is a colloquial term for a pellicle,<ref>Colleen. [https://fermentools.com/what-is-kahm-yeast-is-it-safe/ What is kahm yeast & is it safe?] Fermentools. 2018.</ref> and it is a misnomer because it is not always created by yeast. Similarly, the pellicle on [[kombucha]] is often mistakenly called the "SCOBY". |