Changes

==Characteristics==

===Introduction===

Pellicles form when the surface of the beer is exposed to even small amounts oxygen <ref>[http://www.themadfermentationist.com/2009/11/brewing-sour-beer-at-home.html Brewing Sour Beer at Home. The Mad Fermentationist Blog. Michael Tonsmeire. 11/06/2009. Retrieved 02/28/2015.]</ref> Why microbes in sour/funky beer form a pellicle when exposed to oxygen is unknown. The most likely hypothesis is that the formation of a pellicle allows the organism (particularly [[Brettanomyces]], which prefers aerobic fermentation) to access the small amount of oxygen that is present in the headspace of the fermentation vessel. Another hypothesis, and one that may be less accurate according to Dr. Matt Humbard, is that the ''pellicle'' protects the beer from other microorganisms <ref name="matt"></ref>. Yet another hypothesis that is often cited is that the pellicle protects the beer from oxygen itself <ref>[http://jesterkingbrewery.com/pellicle-photos Jester King Blog on Pellicles. Retrieved 09/24/2015.]</ref>, however arguments for this hypothesis are lacking.