Whatever you do, don’t keep onions in the fridge. Why? We’ll get to that.
How Long Do Whole Onions Last?
When selecting onions at the store, check them for soft spots or mold. Damaged onions don’t last as long. According to the National Onion Association, onions should have little scent and should feel firm. For the longest-lasting onions, keep them whole, with the skin on. Under the best conditions, onions can last weeks, or even months.
The Best Way to Store Onions
Onions like nooks that are cool, dry, and dark. A refrigerator is cold (not cool) and humid (not dry). Put your onions in the fridge and they’re more likely to get soft, which can make them spoil.
If possible, store whole onions away from light. Onions are still living bulbs –light is a cue for them to sprout, and you don’t want them to sprout, because it changes their flavor.Don’t keep whole onions in a plastic bag. Trapped moisture can lead to mold. You want onions to breathe. If they’re in a plastic bag, take them out of the bag.Ideally, use perforated or mesh storage bins for better air flow to help keep moisture levels down.For short-term storage—when you plan to use the onions in a day or two—a bowl on the counter or in a cupboard is just fine.
A perforated plastic bin or wire-mesh basket in a cool cupboard is terrific. A basement is another cool, dark place. Granted, it’s not that handy, but you can always keep a few onions in the kitchen at the ready and have the bigger lot of them downstairs for long-term storage.
How to Store Cut or Chopped Onions
Lots of recipes call for just half an onion. Put the unused half in a plastic bag, seal, and refrigerate up to a week. Pre-chopping or slicing onions can be a handy meal prep strategy for faster weeknight cooking. Pop them into a zip top bag or airtight container and aim to use them within 5 days; their onion-y smell only gets stronger with age.
Can You Freeze Onions?
Whole onions, no. Don’t freeze those. But cut onions? Yes! Freeze chopped or sliced onions in an airtight zip top bag with as much air pressed out as possible and use them within 6 months. Frozen onions are best used for cooking, not for serving raw. Have a ton of onions you want to use up? Make caramelized onions! (They freeze great, too).
Bonus! How to Store Shallots
Shallots are kind of like baby onions. Everything we said above about onion storage goes for shallots, too.
