Once opened and exposed to air, however, harmless “vinegar bacteria” may start to grow. This bacteria causes the formation of a cloudy sediment that is nothing more than harmless cellulose, a complex carbohydrate that does not affect the quality of the vinegar or its flavor.
Wine vinegar has a wide range of normal behaviour: it can get cloudy* or develop sediment, and that's normal. Even filtered vinegar can develop cloudiness and still be perfectly safe.
The “floaties” you see are “mother,” a harmless natural bacteria that may develop after vinegar is opened.
However, over time, it will age and undergo some harmless physical changes. So, don't worry about that ancient bottle you uncovered in the way back of your pantry. That murky look and extra sedimentation are normal, and your apple cider vinegar is still OK to use.
Once opened and exposed to air, however, harmless “vinegar bacteria” may start to grow. This bacteria causes the formation of a cloudy sediment that is nothing more than harmless cellulose, a complex carbohydrate that does not affect the quality of the vinegar or its flavor.
Does Apple Cider Vinegar Expire? While the acidic properties of apple cider vinegar keep it from ever truly going bad, you'll still find an FDA-required expiration date on the bottle—usually between 2 and 5 years. Once opened and exposed to air, the flavor and look of vinegar will slowly begin to change.
If you're noticing a general cloudiness in your vinegar, that's your signal to buy a new bottle. “When the vinegar starts getting cloudy, or the flavor is off, then oxidation has significantly changed the quality of the product,” explains Regusci. “But I wouldn't say spoiled, I would say low-quality.”
So you can tell if the apple cider has turned bad by tasting it without fear of poisoning. If the cider is supposed to be sweet, but you taste a more sour, vinegary taste, then the apple cider has turned bad.
Does Vinegar Go Bad? No, vinegar doesn't expire. Whether it's a bottle of crystal-clear distilled white vinegar or cloudy apple cider vinegar with the “mother,” vinegar has a virtually indefinite shelf life thanks to its high level of acidity (above 4%).
Vinegar mother is just bacteria that feeds on alcoholic liquids, and the fact that one developed in your vinegar just means that there were some sugars or alcohol that weren't completely fermented in the vinegar process. You have a few options with your mother of vinegar.
Some species produce pigments on solid growth medium and can produce different types of polysaccharides. These bacteria are found in substrates containing sugar and/or ethanol, such as fruit juices, wine, cider, beer, and vinegar.
When pasteurization is incomplete or the vinegar is re-inoculated with vinegar bacteria from the air after opening, a slimy, amorphous blob or substance will form and float near the bottom. This is a vinegar mother and is just bacteria that feeds on alcoholic liquids.
Mother of vinegar is a biofilm composed of a form of cellulose, yeast, and bacteria that sometimes develops on fermenting alcoholic liquids during the process that turns alcohol into acetic acid with the help of oxygen from the air and acetic acid bacteria (AAB).
A vinegar mother is a gelatinous disc that looks like a slice of wobbly raw liver.
“It's a little bit of sediment from the apples themselves, and it's also vinegar mother,” which is a natural by-product 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.”
The yeast process the sugar found in the juice and turn it into ethanol and CO2. The CO2 adheres to the yeast, solids, and other compounds like pectin and tannins and, all this floats to the top. This forms a foamy cap or krausen on top of the cider.
Although mother of vinegar looks unappealing, it does not pose a health risk.
Once opened and exposed to air, the flavor and look of vinegar will slowly begin to change. It will often become murkier or have more sediment at the bottom of the bottle, and the “mother” may even form a gelatinous biofilm, made of cellulose, that will float in the bottle or jar.
White distilled vinegar will remain virtually unchanged over an extended period of time. And, while some changes can be observed in other types of vinegars, such as color changes or the development of a haze or sediment, this is only an aesthetic change. The product can still be used and enjoyed with confidence.”
5 If it develops sediments or a "mother" or if it changes color, that's okay—it's still good. Over time, too, the vinegar's acidity will lose some of its potency, but it's still useable. 6 If the taste flattens or the smell becomes too pungent, that's when you should consider tossing it out.
You don't have to refrigerate it once you open it. Instead, store it in a pantry or cabinet, away from direct sunlight. To keep it looking and tasting its best, store it in a glass or plastic container. Keep the lid on when you're not using it.
Fresh apple cider doesn't contain alcohol. It's possible for unpasteurized cider to ferment over time and become alcoholic, creating hard apple cider. If you don't want your cider to become alcoholic, then it's best to drink it within two weeks of making it.