Acetobacter is a genus of obligatory aerobic bacteria that is in the family Actobacteraceae. This family is more commonly known as "acetic acid bacteria" (AAB). Other genera of AAB include Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania and Saccharibacter .
http://www.thebrewingnetwork.com/the-sour-hour-episode-28/ cleaning Acetobacter out of barrels (~47 mins in)
Leads on fermentation: http://www.mdpi.com/2311-5637/4/3/66
Acetic acid is produced by acetic acid bacteria through the oxidation of carbon sources into ethanol, followed by the oxidation of ethanol into acetaldehyde, and finally through the oxidation of acetaldehyde into acetic acid. When ethanol is depleted, acetic acid bacteria can also convert glycerol into cellulose, acetic acid, and carbon dioxide. Acetic acid bacteria have also been linked to elevated levels of acetoin, a pleasant buttery flavor, as well as ethyl acetate .
Alcohol and Sugar Tolerance
Tolerance to ethanol begins to decline in most Acetobacter species and strains starting at about 10% ABV. However, this is species and strain dependent. For example, some strains of A. aceti and A. pasteurianus (80% of strains tested) are unable to grow in 10% ABV. Other genera of acetic acid bacteria such as Gluconobacter and Gluconacetobacter also have a wide range of ethanol tolerances. It is documented that Acetobacter and other acetic acid bacteria are able to grow in wine above 10% ABV, although is is not likely that acetic acid bacteria can grow in wines that are 15% ABV or above. It is considered that no strains of acetic acid bacteria can grow in 15.5% ABV or above .
Most strains are not tolerant of glucose once it is at ~25% of the solution .
Role in Belgian Beer
Acetic acid bacteria have been found in spontaneously fermented beers from Belgium (lambic) as well as America (American Coolship Ales) and Belgian Flanders Red Brown Beers. They are generally found at the air to liquid interface within barrels where they can access oxygen in the headspace. In general, brewers try to limit the impact of acetic acid bacteria in beer due to the higher levels of acetic acid that they can produce .
Role in American Sour Beers
As a Contaminate
Role in Vinegar
(This can be brief, and might get deleted completely since this isn't a vinegar wiki. However most Acetobacter knowledge probably comes from vinegar.)
Additional Articles on MTF Wiki
- Flanders Red Ale
- Scientific Publications
- Mixed Fermentation
- Characterization of acetic acid bacteria in “traditional balsamic vinegar”. Maria Gullo, Cinzia Caggia, Luciana De Vero, Paolo Giudici. 2005.
- Bossaert, Sofie, et al. “The Power of Sour - A Review: Old Traditions, New Opportunities.” BrewingScience, vol. 72, no. 3-4, 2019, pp. 78–88.
- Molecular Wine Microbiology. Chapter 9 - Acetic Acid Bacteria. 2011, Pages 227-255. DOI: https://doi.org/10.1016/B978-0-12-375021-1.10009-8.