why does balsamic vinegar go solid and rubbery when left in a glass bottle for months?

Question

there was also a lot of powdery green mould on top, but that came out easy- the rubbery part had to be cut and probed to slide out the neck of the bottle. it looked and felt a lot like liver- but tougher.

it was good quality vinegar and i dont care about how to keep it, i just want to know why???? what makes this happen, some sort of chemical reaction over time\????

Answer 1

i have kept balsamic vinegar for a long time and it never did that... easy answer you bought cheap vinegar

Answer 2

I refrigerated mine and have had no problems with it (it is also in a glass bottle).