The Best Way to Store Onions

Whether you're making an omelet for breakfast or following a recipe for an exquisite dinner, you're likely to use some form of onion. Unlike many other vegetables, onions can last quite a long time before being used — but only if you follow a few important storage rules. If you keep it in the wrong place, it can spoil much faster than you'd like.

Whole, unpeeled onions feel best in cool conditions, ideally between 7 and 13°C. Since your home is probably not that cool, you can store onions in unheated areas like a garage, basement, or pantry. Onions love dryness and darkness. If exposed to moisture or sunlight, they may start to sprout. Sprouting is not dangerous, but it can change the flavor of the onion. If kept cool and dry, onions can last up to three months.

If you don't have a suitable cool storage place, it's best to keep whole, unpeeled onions in the refrigerator, where they can last up to two months (as long as your fridge isn't too humid). If you have no other option, you can also keep them on the kitchen counter, but keep in mind that in this case, they will only last two weeks to one month. Avoid warmer spots in the kitchen.

Chopped, but still raw onions should always be stored in the refrigerator to avoid contamination. Place them in a sealed container — if possible, choose glass to prevent odor absorption from plastic. A sealed container reduces oxidation and moisture absorption, allowing chopped onions to last up to ten days.

You may have heard that it's not a good idea to store onions and potatoes close to each other. It is believed that onions produce a gas that can cause potatoes to spoil faster, and potatoes release moisture that can spoil onions.

The good news is that you don't need to worry about this. Both products emit low levels of ethylene, so you can store them together without the risk of spoilage. The only potential issue is that potatoes may absorb the onion's smell, but this is not a major concern if you cook them together!

Do your best to keep onions in a cool, dark, dry place with adequate ventilation. If you can't follow all the storage rules, the countertop is an acceptable option, but in this case, it's better to buy onions as needed rather than in bulk to avoid waste.