The bottle has a best by date of 2022 and was opened a few months ago.
Is that common that mold can grow in vinegar?
Best Answer
Normal vinegar concentration (usually around 5% acetic acid) is too acidic to grow mold in the vinegar itself. Mold can sometimes grow on the bottle or on the surface of the vinegar. It isn't dangerous and can be wiped/skimmed off.
Vinegar is produce when acetobacter bacteria consume alcohol and produce acetic acid. The bacteria form a culture as they work. In the case of filtered vinegar, this culture is removed before bottling but letting a bottle of unpasteurized vinegar sit for a while will allow the culture to reform. Unfiltered vinegar often already has some of the mother present.
It is harmless and can be used to start your own vinegar if you have stale wine sitting around.
If your solution grew mold, it would indicate that either the container wasn't sufficiently sterilized before sealing or (probably and) the solution wasn't sufficiently acidic. This can usually be ensured by following a recipe that is known to be good, which should have factors like acidity and water activity accounted for.
As for kahm yeast, it seems that this occurs more frequently on cultured vegetables which would spend some of their time in a less acidic environment (while the culture develops and acidifies). I suppose you could culture it and test it, but when in doubt I'd just toss it.
Best Answer
Normal vinegar concentration (usually around 5% acetic acid) is too acidic to grow mold in the vinegar itself. Mold can sometimes grow on the bottle or on the surface of the vinegar. It isn't dangerous and can be wiped/skimmed off.
What you are seeing is called the mother.
Vinegar is produce when acetobacter bacteria consume alcohol and produce acetic acid. The bacteria form a culture as they work. In the case of filtered vinegar, this culture is removed before bottling but letting a bottle of unpasteurized vinegar sit for a while will allow the culture to reform. Unfiltered vinegar often already has some of the mother present.
It is harmless and can be used to start your own vinegar if you have stale wine sitting around.