Is my black truffle oil which is now three years old still good. I use it only a few times a year because well it's truffle oil, not ketchup. But Is it still good or has it by now lost all the truffley yummyness?
I probably wasn't very 3 years ago (those oils don't taste like truffles, but rather like chemicals IMO), but if you just taste it, you'll know if it's rancid. My guess is that it is not something you want to put in your food at this point.