I am trying to make a balsamic style vinegar. Is there any Italians from
Modena Region (or others knowledgeable) that make balsamic vinegar that can
comment?

I have a batch of vinegar that got a pungent smell. I dumped it and
started some new batches. They have the expected vinegar aroma not the
pungent aroma.
I have no idea why the one batch smelled pungent and noone has been able to
explain it.
I am guessing that I left it too long and the vinegar turned into something
else or I didn't get enough air into it and some anaerobic bacteria beat out
the mother.
The articles I have seen on vinegar making are pretty sketchy. Does anyone
have details on vinegar making and how balsamic vinegar is given that unique
taste?

Sarge