How to tell if raw apple cider vinegar is bad?

December 7, 2025 •

5 min read

Apple cider vinegar's high acidity means it rarely spoils, but its quality can change over time. Here's how to tell if raw apple cider vinegar is bad by checking for unusual odors, tastes, or contamination, and distinguishing normal aging from true spoilage.

Quick Summary

Raw apple cider vinegar rarely spoils, but changes in its taste or smell can indicate quality degradation. Learn to distinguish normal cloudiness and 'the mother' from mold or contamination, and how to store ACV to maintain its potency over time.

Key Points

Check for Mold: Look for any fuzzy black or green patches, especially on the surface, as this is a definite sign of spoilage that warrants disposal.
Distinguish 'The Mother': Don't confuse the harmless, stringy or gelatinous mother culture with contamination; it's a natural part of raw, unfiltered ACV.
Trust Your Nose and Taste Buds: A rotten or musty smell or a flat, metallic, or otherwise unpleasant taste means the vinegar's quality has degraded beyond use.
Proper Storage is Key: Keep your bottle of ACV tightly sealed in a cool, dark place away from heat and direct sunlight to preserve its quality and potency for longer.
Shelf-Life is Long: The high acidity of apple cider vinegar gives it a virtually indefinite shelf life, with expiration dates primarily indicating peak quality rather than safety.

Raw apple cider vinegar (ACV) is a staple for many, used in cooking, health tonics, and even cleaning. Unlike many other food products, its high acidity makes it highly resistant to spoilage. A properly stored bottle can last for years, often well beyond the 'best by' date printed on the label. However, this longevity can lead to confusion about what is normal for raw, unfiltered ACV and what are true signs of spoilage. While harmful contamination is rare, it's possible for quality to degrade over time, affecting taste and potency.

Normal vs. Bad: Understanding the Signs

Identifying whether your raw apple cider vinegar is still in good condition comes down to understanding the visual, olfactory, and gustatory changes that can occur. Raw, unfiltered ACV, often sold with "the mother," has a distinct appearance that can be mistaken for spoilage. The mother is a SCOBY (symbiotic culture of bacteria and yeast) that forms during fermentation and is perfectly safe and beneficial to consume.

Appearance

It's important to know what to look for, and what to ignore, when examining your bottle of raw ACV. Normal changes should not be confused with dangerous spoilage.

Normal: The liquid in raw ACV is naturally cloudy or murky. This is caused by the presence of "the mother" and apple sediment. You may also see stringy, cobweb-like strands or gelatinous globs floating in the liquid, which are all part of the mother culture. Over time, the color may darken, which is a normal part of the oxidation process and not a sign of spoilage. Shaking the bottle can help disperse the mother.
Bad: The first clear sign of spoilage to watch for is mold. While extremely rare due to the high acidity, mold can appear as fuzzy, black, or green growth, typically on the surface of the liquid or around the cap where some air is present. A thick, slimy film that doesn't break up when shaken could also signal a problem, possibly an overgrowth of bacteria. If the liquid has an oily or unusually thick texture, it may be contaminated.

Smell and Taste

Before consumption, your nose and taste buds are the most reliable tools for a final quality check. The distinct, pungent aroma and flavor of ACV are what define it, and any deviation can indicate a change in quality.

Normal: Quality ACV should have a strong, sharp, and fruity apple aroma. The taste should be tangy and acidic. Over many years, the flavor and acidity may weaken or become flatter, but this is a loss of quality rather than spoilage.
Bad: If the vinegar smells musty, rotten, or like overly fermented fruit, it's a sign of a problem and should be discarded. A flat, weak, or metallic taste is also an indicator that the quality has degraded significantly due to oxidation. In some very rare cases of contamination, it might even have an unpleasant, putrid aroma.

Comparison Table: Good vs. Bad Raw ACV


Characteristic	Normal Raw ACV	Potentially Bad Raw ACV
Appearance	Cloudy, hazy, or murky with visible sediment or strands of 'mother'. Color may darken slowly over time.	Fuzzy, black, or green mold growth. Unusual oily or slimy surface texture. Sediment that doesn't disperse easily.
'The Mother'	Present as stringy strands, cobwebs, or a gelatinous blob. Safe and beneficial to consume.	Does not indicate spoilage unless paired with mold. An abnormally thick or large mother can form over time, but is not dangerous.
Smell	Pungent, sharp, and fruity with a distinct apple aroma.	Musty, rotten, putrid, or generally 'off.' Lacks the characteristic strong vinegar smell.
Taste	Tangy, sharp, and acidic. May become slightly milder or flatter over time but remains pleasant.	Flat, weak, or metallic. Could also be excessively sour or bitter. Unpleasant and unappealing.
Safety	Considered safe for consumption indefinitely if stored properly.	Should be discarded immediately. While rare, it's better to be safe than sorry.

Proper Storage for Maximum Shelf Life

Storing your raw apple cider vinegar correctly is the best way to ensure its quality is maintained. The following steps will help keep it fresh and potent:

Keep it in the original container: Use the bottle it came in, preferably glass, as it is non-reactive. Plastic can potentially react with the acidic vinegar over a long period.
Seal it tightly: Oxygen exposure is the primary reason for quality degradation. Always ensure the lid is screwed on tightly after each use to minimize air exposure.
Store in a cool, dark place: Heat and direct sunlight can accelerate the degradation of the vinegar's beneficial properties. A pantry or cabinet away from appliances is ideal.
Refrigeration is not necessary: Raw ACV is shelf-stable and does not require refrigeration. It will not extend the shelf life and might even create condensation.

Conclusion

Ultimately, raw apple cider vinegar is an incredibly resilient product that rarely spoils in the typical sense of food going bad. Normal changes like cloudiness, the presence of 'the mother,' and a slightly fading flavor over time are nothing to be concerned about. However, any truly suspicious signs—such as actual mold growth or a distinctly rotten smell or taste—should be taken seriously, and the product should be thrown out. By paying attention to these few key indicators, you can confidently determine the quality of your ACV and enjoy its benefits for years to come. For more on the specifics of ACV, see this resource from Bon Appétit: Does Apple Cider Vinegar Go Bad? | Bon Appétit.

Lists

Key Indicators of Healthy Raw ACV:

Cloudy or murky appearance due to the 'mother' and apple solids.
Visible, harmless strands or globs of 'mother'.
A strong, characteristically pungent apple aroma.
Sharp, tangy, and acidic taste.

Reasons Your ACV Might Seem "Off" But Isn't Bad:

Oxidation: Exposure to air can weaken the flavor and acidity over a long period, but it remains safe.
Mother Growth: The mother culture can grow larger and more prominent, especially in older bottles.
Sedimentation: Apple solids naturally settle at the bottom of the bottle over time.
Color Changes: A gradual darkening of the liquid is a normal aesthetic change due to oxidation.

Frequently Asked Questions

Apple cider vinegar does not technically expire in the same way other foods do because its high acidity acts as a natural preservative, preventing the growth of harmful bacteria and mold. The 'best by' date on the bottle indicates when its peak quality is expected, not when it becomes unsafe.

The cloudy substance and sediment are commonly known as 'the mother' and are completely normal in raw, unfiltered ACV. It's a natural byproduct of the fermentation process, consisting of beneficial cellulose, bacteria, and yeast.

Yes, the mother is completely safe and beneficial to consume. Many people seek out raw ACV specifically for the added enzymes and probiotics that the mother provides. You can shake the bottle to disperse it or strain it out if you prefer.

Bad apple cider vinegar will have an off-putting, musty, or rotten smell, which is a strong sign of contamination. In contrast, healthy ACV has a sharp, pungent, and distinctly apple-like aroma.

No, refrigeration is not necessary for apple cider vinegar. It is shelf-stable and best stored in a cool, dark pantry or cabinet, away from direct sunlight and heat, to preserve its quality.

A weakening or 'flatter' taste is typically a result of gradual oxidation from air exposure, which reduces the acetic acid content over a long period. The vinegar is still safe to use, but its potency and flavor profile may be diminished.

It is highly unlikely to get sick from old ACV, as the high acidity prevents the growth of most harmful pathogens. The main risks are reduced quality or, in very rare cases, contamination leading to mold. If it looks or smells bad, it's best to discard it.