Does Apple cider vinegar go bad?!
Answers: I've had a jar of it for years now and its got this brown stuff at the bottom of it now should I throw it away?
Apple cider vinegar is apple cider that fermented, became hard apple cider and then went bad. The bacteria responsible for eating the alcohol create the vinegar (BTW, your body metabolizes alcohol into vinegar).
So, technically, it's already gone bad twice. But, it's still good, if you purchased a good bottle, that brown stuff is probably some of the bacteria that created the vinegar. What likely happened is all the alcohol went away, they had nothing to eat and dropped out of the solution and became sediment. You could try straining it out if you wish, I'm assuming its not a whole lot of brown stuff.
I think you'v answered your own question.
'got brown stuff on it' that never sounds good!
The brown stuff is sediment. Cider vinegar doesn't really go bad, it is essentially cider that went 'bad' and didn't become alcohol.
It's still usable for some things but not for human consumption
The stuff on the bottom is called "mother".
It don't go bad, just ignore the stuff.