Vinegar, known since ancient times (with traces found both in the Bible and in some Egyptian papyri), is obtained from the fermentation of low-alcohol liquids due to the action of acetic bacteria, which transform ethyl alcohol into acetic acid. The different types of vinegar depend on the starting base: we can have wine vinegar, alcohol vinegar, apple cider vinegar, and so on. Common to all types of vinegar is the gelatinous mass called the "mother of vinegar." This is nothing more than cellulose produced as a "byproduct" by the active bacteria of acetic acid and is found inside the bottles. The mother of vinegar appears in a stratified gelatinous form, usually on the surface of the containers, as these bacteria require a constant supply of oxygen from the air to act and remain active.

The "mother" was often renewed by extracting it, "peeling" it, discarding the old layers, and then washing it with wine vinegar to "regenerate" it. This procedure did not act so much on the cellulose itself, but rather because the vinegar brought with it new active bacteria, ready to work. Since one of the intermediate elements of the process is acetaldehyde, which has a strongly unpleasant odor, the presence of a smell upon opening the bottle indicates that fermentation is not yet complete.

Finally, it is important to emphasize that, although not very aesthetically pleasing, the mother of vinegar is absolutely harmless. It is possible to continue using the vinegar in which it is contained, as the process by which it forms is a sign and proof of the artisanal nature of the production process and the quality of the raw materials used.