Key takeaways
- To tell if a potato is bad, check its firmness, smell, skin color, mold, and whether the damaged area can be safely removed; a few small sprouts or minor surface discoloration do not always mean the potato must be discarded.…
To tell if a potato is bad, check its firmness, smell, skin color, mold, and whether the damaged area can be safely removed; a few small sprouts or minor surface discoloration do not always mean the potato must be discarded.
5 clear signs a potato has gone bad
1. It feels very soft, wet, or collapsed
A fresh potato should feel firm and reasonably heavy for its size. If it gives easily when pressed, feels squishy, or has sunken patches, its internal structure is breaking down. A potato that is slightly wrinkled but still firm may simply be losing moisture, but deep wrinkles combined with softness indicate spoilage.
Discard potatoes that are leaking liquid, have a wet, slimy surface, or collapse when handled. Do not cut away only the soft spot and use the rest, because decay can spread beneath the skin where it is not immediately visible.
2. It has mold or spreading dark decay
Small, dry marks from handling are not automatically dangerous. However, fuzzy white, green, blue, or black growth is mold and means the potato should go in the trash. Mold can extend below the visible surface, so scraping or trimming it away is not a reliable fix.
Also discard a potato with black, brown, or gray areas that are wet, sunken, expanding, or paired with a bad smell. A small dry bruise may be cut away generously from an otherwise firm potato, but widespread discoloration suggests deterioration.
3. The skin has turned distinctly green
Green skin develops when potatoes are exposed to light. The green color itself is a warning that the potato may contain elevated levels of glycoalkaloids, including solanine. These compounds can cause stomach upset and other symptoms when consumed in significant amounts.
If the green area is only a small patch and the potato is otherwise firm, peel it deeply and remove the green flesh, eyes, and sprouts. Do not eat the peel. If the potato is extensively green, bitter, sprouted throughout, or green beneath the peeled surface, discard it instead of trying to salvage it.
Never eat a potato that tastes bitter or causes a burning sensation in the mouth. Spitting it out does not guarantee that every potentially irritating compound has been removed, but it is a useful signal to stop eating it.
4. It smells sour, musty, fermented, or rotten
Fresh potatoes have a mild earthy smell. A sour, sweet-fermented, chemical-like, musty, or rotten odor indicates bacterial or fungal spoilage. Smell the potato after removing it from the bag, since odors from other spoiled vegetables or damp packaging can transfer to the outside.
If the odor remains after rinsing and the potato is soft, wet, moldy, or discolored, discard it. Do not taste a questionable raw potato to decide whether it is safe.
5. It has extensive sprouts or unusual internal damage
Small sprouts on a firm potato do not automatically make it unsafe. Remove each sprout and its surrounding “eye” with a knife, then peel the potato and inspect the flesh. Use it promptly rather than storing it for several more weeks.
Discard the potato if it is heavily sprouted, green, shriveled, bitter, or soft. When cut open, a potato with a hollow cavity, blackened interior, watery flesh, or a strong odor should also be discarded. A small dry hollow or a limited bruise can sometimes be cut away, provided the remaining potato is firm, normal-smelling, and free of green coloration.
Quick decision guide: keep, trim, or throw it away?
| What you see | What it usually means | What to do |
|---|---|---|
| One or two short sprouts; potato is firm | Early sprouting from age or warmth | Remove sprouts and eyes, peel, cook soon |
| Small dry bruise or shallow cut | Physical damage, not necessarily spoilage | Cut away at least 1 inch around and below the damaged area |
| Small green patch on otherwise firm skin | Light exposure and possible glycoalkaloid buildup | Peel deeply and remove all green flesh; discard if extensive |
| Soft, wet, leaking, or slimy areas | Active decay | Discard the entire potato |
| Fuzzy mold, rotten odor, or widespread black decay | Fungal or bacterial spoilage | Discard the entire potato |
How to inspect a potato safely
- Check the bag first. Separate any leaking or moldy potato so it does not contaminate the others.
- Feel the potato. Keep it only if it is firm, dry, and intact enough to handle.
- Look at the skin. Check for green areas, fuzzy growth, spreading dark spots, and deep wet damage.
- Smell it. A strong sour, musty, or rotten odor is a reason to discard it.
- Cut only sound potatoes. If you are removing a small bruise or sprout, use a clean knife and inspect the inside before cooking.
- Wash before preparation. Scrub firm potatoes under cool running water, even if you plan to peel them.
How long do potatoes last?
Storage conditions matter more than a single fixed expiration date. Whole potatoes usually keep for about 1–2 weeks in a warm kitchen, roughly 2–3 weeks in a cool, dark pantry, and commonly 1–2 months in suitable cool storage. These are practical ranges, not guarantees; inspect every potato before use.
| Storage location | Useful temperature target | Typical quality window |
|---|---|---|
| Warm kitchen cupboard | Above about 60°F (16°C) | About 1–2 weeks |
| Cool, dark, ventilated pantry | About 45–55°F (7–13°C) | About 2–3 weeks |
| Cool cellar or suitable long-term storage | About 45–50°F (7–10°C) | About 1–2 months, sometimes longer |
Store potatoes in a breathable paper bag, cardboard box, or ventilated basket rather than a sealed plastic bag. Keep them dark and dry, away from onions and other produce that can accelerate deterioration. Avoid washing potatoes before storage because trapped moisture encourages mold.
Can you cook a potato that has sprouted?
Usually, a firm potato with a few small sprouts can be used after the sprouts, eyes, green skin, and any bitter or damaged flesh are removed. Cooking does not reliably eliminate all glycoalkaloids, so do not rely on heat to make a heavily green, bitter, or badly sprouted potato safe.
When in doubt, throw it out. The cost of replacing one potato is small compared with the risk of eating food that is visibly moldy, rotten, slimy, strongly odorous, or extensively green.
Frequently asked questions
Are wrinkled potatoes safe?
A mildly wrinkled potato may still be usable if it remains firm, dry, normal-smelling, and free of mold or green skin. Deeply shriveled potatoes that are soft, hollow, or bitter should be discarded.
Can a potato with a small black spot be eaten?
A small, dry bruise can usually be cut away generously. If the spot is wet, spreading, sunken, moldy, or accompanied by an unpleasant smell, discard the whole potato.
Should bad potatoes go in the compost?
Follow your local composting rules. Moldy or rotting potatoes can sprout and may attract pests, so placing them in a sealed household-waste bag may be preferable where home composting is not designed for food scraps.
