Vinegar

[MWB]

I have a bottle of Malt Vinegar that I've had for about a year. I went to use it tonight but it's got mould in a thick layer on the top!!! What the.............................? I thought vinegar can't go off like that?!

[funnygirl]

Yuk, sounds vile!
Throw it away. I threw away a bottle of malt vinegar just before christmas as the date was way out, like May 07.
Like you, I thought vinegar could not go off!
Maybe it is the hops or something!!

[chazza]

We once had a bottle of vinegar that we found in the back of the cupboard with something growing in it! It looked like a big bit of sliced onion that had been fried up! Or a tapeworm!

[Minimatronic]

the answer above sounds like a vinegar mother ... i don't know much about them, a few years ago i worked in a restaurant and was totally shocked to find one in the industrial sized vinegar bottle! apparently they're safe, that's what i was told, but then it wasn't the most salubrious restaurant! don't know about the mould over the top though :s

[Clanad]

Mould and other bacteria cannot grow in vinegar. What you're seeing is, as Minimatronic states, is the "mother"... see here:
Mother of vinegar is a slime composed of a form of cellulose and acetic acid bacteria that develops on fermenting alcoholic liquids, which turns alcohol into acetic acid with the help of oxygen from the air. It is added to wine, cider, or other alcoholic liquids to produce vinegar.

Mother of vinegar can also form in store-bought vinegar if there is some non-fermented sugar and/or alcohol contained in the vinegar. While not appetizing in appearance, mother of vinegar is completely harmless and vinegar does not have to be discarded because of it. It can be filtered out using a coffee filter, or simply left in and ignored. (Source: Wikipedia).
A lot of us take a tablespoon of unfiltered apple cider vinegar for health benefits each day. The unfiltered version leaves the 'mother' in and is reputed to be beneficial. It doesn't affect the quality of the vinegar at all...

[willowbee]

the mother is also called a 'scoby' and a scoby is used to make Kombucha which is a beautiful drink from ancient times. There is a huge worldwide network associated with Kombucha.
Look it up on net :)