Changes

There are also various barrels on the market that are very small (1-5 liters). These barrels are designed as novelty items or perhaps aging spirits where oxygen exposure might not be as big of an issue as it is for beer (especially sour beer). The problems of a low volume and a high surface area expressed above are an even greater a threat when aging sour beer in such a small barrel. When ''Brettanomyces'' is exposed to oxygen, it produces acetic acid and small barrels can quickly produce too much acetic acid. Although aging for a very short amount of time in these very small barrels (perhaps 1 month or less) might produce favorable results, we recommend against aging sour beer in barrels that are smaller than 5 gallons (19 liters). Some people warn that the manufacturer of these small barrels uses very thin staves even for their larger version (20 liter). They are sold by a large number of outlets, and can be identified by their spigot and dot in the center of the head <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1754245311270342/?comment_id=1754342934593913&reply_comment_id=1754592201235653&comment_tracking=%7B%22tn%22%3A%22R2%22%7D James Shamas. Milk The Funk Facebook group. 07/13/2017.]</ref>.