That sharp, nail-polish taste in your pomegranate is almost certainly the result of fermentation happening inside the fruit. Sugars in the arils break down into ethanol and then into ethyl acetate, a compound that is literally the main solvent in most nail polish removers. The fruit can look perfectly fine on the outside while this chemical process is well underway inside.
What Creates That Chemical Taste
When pomegranate arils don’t get enough oxygen, their cells switch from normal respiration to a backup mode called anaerobic respiration. Instead of burning sugars cleanly with oxygen, the cells start producing ethanol (alcohol) and acetaldehyde as byproducts. These compounds then react with each other to form ethyl acetate, which has that unmistakable solvent smell. Pomegranates are especially sensitive to low-oxygen conditions compared to many other fruits, so this shift can happen readily.
Certain natural aromatic compounds in pomegranate can amplify the effect. One key aroma molecule found across pomegranate varieties has been described by researchers as having a “pine, polish, and woody aroma.” In a fresh, well-stored fruit, this compound blends into the complex flavor profile you expect. But when fermentation adds ethyl acetate on top of it, the two together create an overwhelming nail-polish sensation that’s hard to miss.
Why It Happens Inside a Normal-Looking Fruit
Pomegranates have a thick, leathery rind that acts as a sealed chamber around the arils. That’s great for protecting the fruit during transport, but it also means problems inside stay hidden. If the fruit experienced cold damage at any point during storage or shipping, the cell membranes in the arils can break down. Cold stress triggers a cascade: membranes lose their structure, cells leak their contents, and the normal metabolic machinery stalls. The fruit’s energy production drops, oxygen circulation inside the rind decreases, and fermentation kicks in.
This type of cold injury, called chilling injury, shows up internally as browning of the white pith between arils and a shift in aril color from bright red toward brown. But these changes can be subtle or limited to one section of the fruit. You might cut open a pomegranate that looks completely normal on the outside and find that only a portion of the arils taste off, while the rest are fine.
Yeasts and Bacteria Speed Things Up
Fermentation isn’t always just the fruit’s own cells misbehaving. Pomegranates naturally carry yeasts and bacteria on their surfaces and in tiny cracks in the rind. The dominant spoilage yeasts produce off-flavors more aggressively than the bacteria do, and they get to work as soon as conditions favor them: warmth, moisture, a small wound in the skin. Acetic acid bacteria also contribute, converting alcohol into vinegar-like compounds that add a sour, sharp edge to the chemical taste.
Once microbial fermentation begins, carbon dioxide builds up inside the sealed rind. In spoilage studies, CO₂ levels inside packaged pomegranate products climbed by 6 to 10 percent per week, eventually reaching concentrations high enough to further starve the arils of oxygen and accelerate the whole cycle.
Pre-Packaged Arils Are More Prone
If you bought a container of ready-to-eat pomegranate arils rather than a whole fruit, the odds of encountering that nail-polish flavor go up. Packaged arils sit in sealed plastic containers with modified atmospheres designed to extend shelf life by reducing oxygen. In theory, this slows ripening. In practice, pomegranates are unusually sensitive to low oxygen. Research on packaged pomegranates found that fruit stored in very low-oxygen conditions accumulated significantly more fermentative compounds, including acetaldehyde, ethanol, and ethyl acetate, than fruit stored with moderate oxygen levels. Taste scores dropped accordingly.
The packaging film itself matters. Some films create near-airtight seals that push oxygen levels too low, essentially creating anaerobic conditions inside the container. If the package sat in a warm spot during transit or on the store shelf, microbial activity would compound the problem.
Is It Safe to Eat?
A pomegranate that tastes like nail polish is unpleasant, but a small amount is unlikely to harm you. Pomegranate juice and flesh are generally considered safe, and the fermentation byproducts involved (ethanol and ethyl acetate) are the same ones present in wine and vinegar. The issue is more about quality than toxicity.
That said, fermentation is an early step on the road to full spoilage. If you notice mushy, brown arils alongside the chemical taste, the fruit has progressed past simple fermentation into decay. Brown arils typically appear first around the outer edges of the fruit, closest to the rind. Any sliminess, visible mold, or a strong vinegar smell means the fruit should be discarded entirely rather than picked through.
How to Avoid It
Whole pomegranates last one to two weeks at room temperature, kept away from direct sunlight. Refrigeration extends that to roughly two months. Once you remove the arils, they keep for five to seven days in the fridge. For longer storage, freezing arils preserves them for up to a year without fermentation risk.
When selecting a pomegranate at the store, pick it up. It should feel heavy for its size, which indicates juicy, intact arils. The skin should be firm and taut with no soft spots, wrinkles, or cracks. A fruit that feels light or has give when you press it may already be drying out or fermenting internally. Color varies by variety and isn’t a reliable freshness indicator, but any dark, wet-looking patches on the rind suggest damage underneath.
For pre-packaged arils, check the sell-by date and inspect the container for any cloudiness in the juice pooling at the bottom. Swollen or puffy packaging is a sign that CO₂ has built up from fermentation inside. If the arils look dull or brownish rather than glossy and jewel-toned, pass on them. Once you get them home, keep them refrigerated and eat them within a few days rather than pushing the expiration date.