What is a SCOBY?

​A SCOBY (for symbiotic culture of bacteria and yeast) is a syntrophic mixed culture, generally associated with kombucha production wherein anaerobic ethanol fermentation (by yeast), anaerobic organic acid fermentation (by bacteria), and aerobic ethanol oxidation to acetate (by bacteria) all take place concurrently along an oxygen gradient. A gelatinous, cellulose-based biofilm called a pellicle forms at the air-liquid interface and is also sometimes referred to as a SCOBY. Either samples of this pellicle or unpasteurized kombucha can be used similarly to Mother of vinegar to begin fermentation in pasteurized sweet tea. [1] Referring to the cultures as a "colony" is misleading, because the term colony implies a group of genetically identical or nearly identical organisms living together. The species comprising the mixed cultures vary from preparation to preparation, but generally include Acetobacter bacterial species, as well as various Saccharomyces and other yeast types. SCOBY cultures used in beverage production can produce a structure referred to as a "mushroom," which is also biologically misleading, because mushrooms are a completely unrelated group of fungi. It often forms in vinegar in jars of pickled foods.