Hint: Keep them away from your potatoes!

By Corey Williams
June 15, 2020
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Make the most of your onions and keep them fresh for as long as possible. Here’s everything you need to know about onion storage:  

How Long Do Onions Last? 

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How long onions last depends on how they’re stored, but onions do have a much longer shelf life than other types of produce (a few months). 

It also depends on the type of onion you’re dealing with: Sweet onions, harvested in spring and summer, have a shorter lifespan because of their higher moisture content. Dry bulb onions, meanwhile, are specifically designed to withstand long periods of storage.

How to Store Whole Onions

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Your first instinct when it comes to food storage may be to seal everything up in a lidded or zipped container and toss it in the fridge. In this case, though, lack of ventilation speeds up the decaying process. 

It’s best to store dry bulb onions in a cool, dry, dark place that gets plenty of air movement, according to the National Onion Association

The Spruce Eats recommends using an old (but clean!) pair of pantyhose to store your dry bulb onions. It’s kinda odd, but it works—it gives the onions room to breathe, while saving you a ton of counter space. This is especially helpful if you’re an avid cook and use a lot of onions. 

If you feel kinda weird about hanging underwear in your kitchen (we feel ya), you can buy cheap mesh bags on Amazon that are specifically designed for onion storage. Same idea, just a little less quirky. 

Sweet onions are a different story. If you’re not planning to use them in the next week or so, the NOA suggests refrigeration. However, you should be sure to “use a low humidity setting; they must be kept dry.” Also, it’s important to keep them away from other fruits and veggies in the fridge, as some will absorb the onions’ pungent odor. 

Tip: Don’t store onions near potatoes. The chemical reaction will actually cause both to spoil faster. 

How to Store Cut Onions

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Unlike whole onions, refrigeration is the only way to go when it comes to sliced, diced, or otherwise cut onions. 

Seal those suckers up in plastic wrap or a zip-top bag and store in the fridge for up to 10 days. 

How to Store Cooked Onions

Keep leftover cooked onions in a tightly sealed container in the fridge for about five days. 

Make sure to store them immediately, as cooked onions can start to develop bacteria quickly at room temperature. 

Can You Freeze Onions? 

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Yes, you can absolutely freeze onions! With one caveat: The freezing process will deteriorate the texture, so it’s best not to use them raw after they’ve thawed. Frozen onions are perfectly suitable for cooking, however, and can be convenient to have on hand. 

How to Freeze Onions

It’s super easy to freeze onions. Just follow these simple steps:

  1. Peel and cut the onions. It doesn’t matter if you chop, dice, or slice—choose the cut that will be most convenient for the recipes you have planned. 
  2. Place them in a freezer bag. Before you seal the bag, squeeze out all the excess air. 
  3. Label with the date and freeze. You can keep onions in your freezer for about 6 months. 

Tip: Instead of freezing in one big bag, fill several small bags with the amount you’d typically use in one recipe. An onion’s texture will deteriorate each time it’s frozen, so it’s best to only thaw the amount you plan to use at once. 

How Can You Tell If an Onion Is Past Its Prime? 

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Good onions are firm and dry. If your onion is mushy, slimy, or (God forbid) moldy, throw it away or compost it.