Archeologists have found vinegar in Egypt that dates to around 3000 BC, so it might seem like the stuff could never spoil. But if you have a bottle of red wine vinegar that’s been lurking around in your cupboard for half a dozen years, it may not be what it once was.
Many people think vinegar is what’s implied by the word’s roots—sour wine, or in French, vin aigre. In reality, once all the alcohol in a bottle of wine has fermented into vinegar, what’s left, chemically speaking, is mostly water with a small percentage of acetic acid—within the 4%–8% range by volume, in the US.
Vinegar loses its luster way slower than most other foods, so it’s often hard to detect its deterioration—because in the same way vinegar preserves foods (e.g., pickles), it also acts as its own preservative. Bacteria can have a tough time growing in such an acidic environment, thus warding off decay. But vinegar will eventually change over time, losing vibrancy as its volatile compounds oxidize. Some vinegars are meant to age (see: balsamic, sherry, Chinkiang black vinegar), and to a certain degree, that can be part of those vinegars’ charms. In my experience, anything less concentrated (like vinegar made from apple cider, rice, wine, and beer) won’t fare as well over time. The pH scale measures how acidic (or basic) something is—the lower (or higher) the number is from a neutral midline of 7, the more inhospitable it generally is to bacteria and spoilage. Water is usually neutral, and vinegar typically ranges between 2 and 3.
But with all that acidity, can vinegar actually go bad? Chris Crawford, creator of Brooklyn-based Tart Vinegar, says an off bottle won’t have any real vinegar character: “It won’t have tartness, acid, it will taste bad, never any question. There’s no middle ground. I think people should trust their palates more than just an expiration date.”
How long does vinegar last, and where should you store it?
Crawford preaches that while most vinegars are pretty durable, certain bottlings should be stored with extra care. “There are some [unpasteurized] vinegars I do store in the fridge,” same with any “raw” vinegar with the mother still floating in it. “I’m not as concerned about another vinegar mother growing, but there is something about when it continues to ferment. It will deteriorate over time, and start to dull a little bit.”
Cole Pearsall, cofounder of experimental vinegar brand Acid League, says that “Fridge space is highly coveted in my house,” so he suggests storing vinegar bottles “in an area that doesn’t have fluctuating temperatures, and is dark—let’s just say a cupboard away from the oven. Heat typically increases chemical reactions.” Keeping unpasteurized vinegars at a cooler temp will slow down any further fermentation.
Katerina Mountanos, founder of Greek olive oil (and vinegar) company Kosterina, noticed the vigor of vinegar’s flavors can be muted by cold temperatures. “So don’t keep it in the garage in wintertime,” she says. The cold won’t harm the liquid, but it’s wise to bring it up to room temperature before using for maximum flavor.
