Question: I have a bottle of red wine vinegar that I purchased and opened about a year ago. I’ve noticed that it’s become cloudy. Is it still safe to use?
Answer: Your vinegar should be fine, provided you’ve been storing it properly.
From a safety standpoint, commercially produced vinegar has a virtually indefinite shelf life, says the Vinegar Institute, an association that represents most of the world’s largest vinegar manufacturers.
And it’s not unusual for vinegar to develop a haze or sediment, or to change color, after it has been stored for some time, says the Institute. Those changes in appearance do not make the vinegar unsafe to use, it adds.
From a quality standpoint, though, prolonged storage can affect both the appearance and the flavor of many vinegars. In the case of opened wine vinegar, you’ll likely start to see at least some quality deterioration after a couple of years.
To help keep vinegar at its best, store it in a cool, dark area and keep it tightly capped after each use.