Colloquial term (also vinegar cream or vinegar fungus) for the gelatinous, stringy layer of Acetobacter (acetic acid bacteria) that forms on the surface of the liquid during vinegar production. If complete fermentation has not taken place, this can also form in commercial vinegar. Despite its unsightly appearance, it is completely safe for consumption. It is also inoculated as a "starter" during production. See also under cream.
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