It often is sold unfiltered and unpasteurized with the mother of vinegar present, as a natural product.

When a bottle of vinegar is opened, mother of vinegar may develop.

These feed on the mother of vinegar and can occur in naturally fermenting vinegar.

While not appetizing in appearance, mother of vinegar is completely harmless and the surrounding vinegar does not have to be discarded because of it.

Mother of vinegar can also form in store-bought vinegar if there is some non-fermented sugar and/or alcohol contained in the vinegar.

Unpasteurized or organic ACV contains mother of vinegar, which has a cobweb-like appearance and can make the vinegar look slightly congealed.

Fast methods add mother of vinegar (i.e., bacterial culture) to the source liquid before adding air using a venturi pump system or a turbine to promote oxygenation to obtain the fastest fermentation.

Turbatrix aceti (Vinegar eels, Vinegar nematode) are free-living nematodes that feed on the microbial culture, called mother of vinegar used to create vinegar, and may be found in unfiltered vinegar.