Onions
Quick answer: Whole raw onions last up to 30 days in a cool, dry pantry or up to 60 days in the fridge. Once cut, they keep 3-7 days refrigerated. Frozen diced or sliced onions stay good for 10-12 months.
Onions are the one ingredient that feels like it lasts forever, until you reach for one and find a soft, moldy mess at the bottom of the bowl. The good news: stored right, a whole onion can easily go two months in the fridge or a month on the counter. The bad news: most of us aren't storing them right.
Pantry
Refrigerator
Freezer
How to store onions
Keep whole onions in a cool (45-55°F), dark, well-ventilated spot with low humidity, a pantry shelf or open basket works better than a plastic bag. Never store them next to potatoes (they speed each other's spoilage). Once you've cut into one, seal it tightly and refrigerate at or below 40°F.
How to spot spoilage
Toss it if it feels soft or mushy, shows gray or black mold, smells sour or rotten, or has gone wet and slimy at the base. Sprouting is a sign it's past its prime, but the onion itself may still be usable in cooking if the flesh is still firm and odor-free.
Use it up before it spoils
- Caramelize a big batch low and slow, then freeze in tablespoon-sized portions for instant flavor bombs.
- Dice and fold into a quick frittata or scrambled eggs.
- Simmer into a simple French onion soup with whatever broth you have on hand.
- Pickle slices in vinegar, salt, and a pinch of sugar, ready in an hour, lasts weeks in the fridge.
- Chop and freeze flat in a zip-lock bag so you can snap off exactly what you need later.
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Best ways to preserve
- freeze
- dehydrate
- ferment
- pickle
- dry
Nutrition at a glance
Per 55 g (1/2 medium onion)
| Calories | 22 |
|---|---|
| Protein | 0.6 g |
| Carbohydrates | 5.1 g |
| Fiber | 0.9 g |
| Sugar | 2.3 g |
| Fat | 0.1 g |
| Saturated fat | 0 g |
| Sodium | 2 mg |
Source: USDA FoodData Central. Onions, raw (SR Legacy)
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Frequently asked questions
Can you freeze onions?
Yes, diced or sliced onions freeze well without any blanching and last 10-12 months. Spread them on a sheet pan to freeze individually first, then transfer to a bag so you can grab just what you need. Whole onions can be frozen after blanching but will be soft, so they're cooking-only after that.
Do onions need to be refrigerated?
Whole, uncut onions actually do better outside the fridge, a cool, dry, ventilated spot keeps them fresh for up to 30 days. The fridge extends that to 60 days if you have the space. Once cut, refrigeration is non-negotiable: seal them tightly and use within 3-7 days.
How long do onions last after cutting?
Cut onions last 3-7 days in the fridge when sealed in an airtight container or bag. The tighter the seal, the better, both for longevity and for keeping the rest of your fridge from smelling like onion.
How can you tell if an onion has gone bad?
A bad onion feels soft or mushy, shows gray or black mold, smells sour or rotten, or is wet and slimy at the base. A firm onion that's started to sprout may still be usable in cooked dishes, just cut away the sprout and check that the flesh underneath is solid and odor-free.
Can you store onions with potatoes?
No, keep them apart. Onions and potatoes stored together accelerate each other's spoilage. Give each its own cool, dark, ventilated spot and both will last significantly longer.