"Bob (this one)" > wrote in message
...
>
> They don't become rancid. They will lose flavor and acidity over time, but
> it's a long time. Vinegar doesn't spoil, as such.
>
> Pastorio

Which reminds me about something odd that happened recently. I had some
balsamic vinegar I'd decanted into a pouring bottle that developed a mother.
I set it aside with the idea of using the mother to make some red wine
vinegar and promptly forgot about it. I came across it a few weeks ago and
there was a layer of mold across the top.

The mother had gotten big enough that the top of it was no longer covered
with liquid. Is the mother not as acidic as the rest of the vinegar? Or
did my vinegar get contaminated with something that allowed mold to grow?
Or does balsamic vinegar (at least the cheapo grocery store stuff like this)
contain enough extra ingredients that mold can form?

Anny