I am enthusiastic but ignorant in the kitchen.
Over the holidays i was in charge of Bearnaise for the filet, (faw-faw-faw....) at one family gathering, and if I do say so myself, I made an excellent sauce, (I use a blender for sauces, I'm too lazy to whisk by hand, and besides - who wants to risk "breaking" food?)
I used a very nice white wine vinegar, (a bit more costly than any ingredients I would spring for under ordinary- read: cooking just for me and Himself- circumstances,) and actual shallots, (merely over-priced, full-of-themselves onion wannabes, IMO.)
Well, here it a month and a half later, and I thought I'd make a variation on the Bearnaise, (a bit of tomato paste added to the standard ingredients,) for chicken, so I pulled the vinegar out of the pantry.
There was something on top of the bottle that looked alive, absolutely grotesque, and I gagged, put it aside and grabbed the balsamic.
It all turned out nicely, thank you, but I was curious about that... thing.
I'm glad I didn't throw the vinegar away, apparently "mother" is harmless and a sign that the process of fermentation has been continuing.
The things you learn if you live long enough.....
(It's still an ugly thing to think is still in ones cupboard.)