Apple cider vinegar punches up pickled onions and coleslaw, forms the bedrock of so many salad dressings, marinades, and condiments, and might even be the secret to tender, ultra-flaky pie crust. I always keep a bottle on hand. But if your pantry is anything like mine, chances are there’s an ancient bottle of apple cider vinegar hiding in your cabinet’s darkest corner.
So if you recently unearthed a cloudy, years-old bottle of vinegar, you’re probably wondering: Does apple cider vinegar actually go bad? And what is that cloudy sediment floating around the bottle, anyways?
Here’s the bottom line: When stored properly, apple cider vinegar never really expires, though it may undergo some changes in taste and appearance over time.
What is the cloudy stuff in my apple cider vinegar?
If you’ve had that bottle of apple cider vinegar for a while now, you might notice the vinegar becoming hazy or separating, with cloudy sediment collecting at the bottom of the bottle. This is most likely to happen in raw, unfiltered vinegar (the kind usually touted to have purported health benefits), but it can happen in filtered vinegar too.
“The cloudy stuff is one of two things, or a combination of the two,” explain Joanne Krueger and Dan Lehrer, who produce artisanal apple cider vinegar from apples grown at their Sonoma county orchard. “It’s a little bit of sediment from the apples themselves, and it’s also vinegar mother,” which is a natural byproduct of the fermentation process. “The vinegar mother grows over time, and that’s usually the swirly stuff that people see at the bottom of the bottle.”
Or maybe you’ve surpassed the innocent floaters and your vinegar has grown a full-on layer of murk. Not to fear: Even when it’s large, the vinegar mother is still good to use. “Depending on how rustic you like it, you can either cap it and really shake it up (to break up the mother), or strain it through a tea strainer and use it,” Krueger says.
The vinegar mother is completely safe to consume. In fact, Sandor Ellix Katz, author of The Art of Fermentation, notes that candied vinegar mother (called nata de coco or nata de piña, depending on the type of vinegar used) is a delicacy in Filipinx cuisine. “It’s just really thick pieces of the mother of vinegar that forms on coconut or pineapple vinegar, sliced up and candied.”
Does apple cider vinegar go bad?
Apple cider vinegar’s antimicrobial properties make it self-preserving, which means that technically, it never expires. A sealed bottle of apple cider vinegar will last indefinitely on your shelf; however, exposure to oxygen—which happens each time you open the bottle—changes the vinegar’s taste and appearance over time.
“That’s why most vinegars are pasteurized and very well sealed, to protect them from oxygen,” Katz says.
While apple cider vinegar does not technically have an expiration date, it will lose its acidic nature over time. In fact, with enough time and oxygen exposure, raw vinegar “will eventually turn to water,” says Kirsten K. Shockey, author of Homebrewed Vinegar and co-founder of The Fermentation School.
But don’t get too worried: If you’re just opening the bottle to make salad dressing, then closing it right away, you likely won’t introduce enough oxygen for any significant changes to happen—at least not for a while.