Changes

There is no scientific basis for the idea that a small amount of oxygen itself that is dissolved during wort souring has a great effect on the flavors that ''Lactobacillus'' produces. Regardless, some brewers report more consistent results when purging oxygen with CO₂. See [[Lactobacillus#Effects_of_Oxygen|Effects of Oxygen on ''Lactobacillus'']] and [https://www.facebook.com/groups/MilkTheFunk/permalink/1778865588808314/ this MTF thread] that discusses the anecdotal experience of brewers who do not purge with CO2CO<sub<2></sub>. The effects of oxygen on the beer could lead to other stability issues with the beer because the exposure to oxygen during wort production is thought to play a role in beer staling (see [[Aging and Storage]]), although hot side aeration is also thought to be a minor problem if at all <ref>[http://beersmith.com/blog/2014/01/31/flavor-stability-in-beer-with-dr-charlie-bamforth-beersmith-podcast-74/ Charlie Bamforth. Interview on BeerSmith about Hot Side Aeration. 01/31/2014. Retrieved 08/18/2017.]</ref>, and the impact of hot side aeration on sour beer has not been studied. Some brewers believe that purging all oxygen out of the system will help to prevent contaminating microbes that are aerobic (microbes that require oxygen) from creating [[Isovaleric_Acid#Kettle_Souring|isobutyric acid]]. Oxygen does not play a role in the production of [[Butyric Acid]] in wort soured beers because this compound is produced by anaerobic bacteria (bacteria that requires the absence of oxygen). Air/dust can carry contaminating microbes, which is a potential problem (see [[Wort_Souring#Contamination_Concerns|Contamination Concerns]] above), however, if the air is filtered somehow before entering the fermenting vessel then the oxygen itself shouldn't pose a problem to souring wort. Follow the links in this paragraph for more information.