How to Preserve Cut Onions Without Refrigeration

It’s common knowledge that you should refrigerate an onion after cutting it. But what if you don’t have power? Or what if your fridge is packed to the max so you need to store your chopped onions without a refrigerator?

Let’s talk about that today, shall we?

Can Cut Onions Be Stored at Room Temperature?

It’s not ideal to store them at room temp once cut. The best thing to do once you’ve cut the onion is to store it in the refrigerator. 

But wait … this is a post about preserving cut onions WITHOUT a refrigerator?!

I hear you. We’ll get to that in the next section 😉 

How Long Can Cut Onions Last Without a Fridge?

Because cut onions are prone to developing bacteria fast, they won’t last longer than a day without refrigeration. And I wouldn’t suggest pushing the limits there.

That said, I’m a gardener, so “cut” onions can mean two different things in my mind (and possibly yours?). 

If you’re referring to whole white, yellow, vidalia, or red onions that you have already diced up, then you should probably toss any remaining dices into the compost bin, out to the chickens, or simply in the trash. 

If you’re thinking about green onions that you grow using the “cut and come again” method, then you can harvest however much you like and place in a jar with water in the bottom. You can then place this jar on a windowsill or kitchen counter. 

They should last roughly 2 weeks when stored this way at room temperature. 

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How to Preserve Cut Onions Long Term Without Refrigeration

Since cut onions spoil quickly, you’ll want to take the extra step to preserve the onions if you don’t want to store them in the fridge. 

Here are the best ways to store cut onions long-term for months or even years without refrigeration.

1. Dehydrating

One way to preserve cut onions is by dehydrating them. Dehydration is the process of removing water from food, which prevents the growth of microorganisms and bacteria that cause spoilage. 

You can preserve chopped onions for months or even years with this method. Cut onions can be dehydrated using a dehydrator or an oven set to a low temperature.

To dry onions in a dehydrator, peel and slice thin, then spread them out on the dehydrator racks. 

Set the dehydrator to a low temperature, around 115 degrees Fahrenheit, and let it run until the onions are dry and brittle. That usually takes 8-12 hours. I’ve even let them go overnight before. 

Once they’re done, store the dried onions in an airtight container in a cool, dark place.

To dehydrate in an oven, preheat it to 175 degrees Fahrenheit (or lower if your oven allows it). Line a baking sheet with parchment paper and spread the onion dices or slices in a single layer. 

Bake for 1-2 hours or until the onions are dry and crisp. Remove from the oven and let cool completely before storing in an airtight container.

If you want to store cut onions without the smell, dehydration is the way to go. They may stink a bit while they are dehydrating, but they are almost odorless once they’re done. 

Dehydrated onions last for several months to a year or more when stored properly. 

To use, simply rehydrate by soaking in water for 10-15 minutes. If you’re using them for cooking, you can add them directly to the pot or pan without rehydrating first.

2. Canning Onion Relish

Onion relish is a delicious way to enjoy chopped or minced onions without having to refrigerate them. 

Onion relish is a condiment made from chopped onions and pickling spices. It’s typically used as a topping for burgers or hot dogs, but we actually use it to add flavor to all sorts of dishes. 

To make onion relish, chop onions and mix them with vinegar, salt, and sugar. You can also add other spices to taste (such as mustard seed or dill) and pour the mixture into the jars.

For exact measurements and steps, I recommend Healthy Canning’s onion relish recipe. 

Finally, seal the jars and process them in a boiling water bath for 10 minutes. 

The vinegar acts as a preservative, preventing the onions from spoiling. And since the relish is stored in a sealed jar, bacteria won’t be able to grow. 

When canned properly, this onion relish can last for years on your shelf—though it disappears from our shelves quickly!

3. Freezing Chopped Onions for Quick Meals

If you’re looking for a quick and easy, consider just storing your diced onions in the freezer, preferably in an airtight container. 

We use a vacuum sealer to prevent freezer burn. It’s a great way to preserve food quickly if you just happen to cut up one too many onions than the recipe called for. 

When ready to use, just thaw the onions in a bowl of warm water for about 10 minutes. If you’re using them in something like a slow cooker recipe, you don’t have to thaw them first. 

Frequently Asked Questions

How Do I Store Red Onions Once Cut?

The best method to store red onions is in the fridge in a ventilated container. You can also wrap them in plastic wrap or place in a zip-top bag with the air squeezed out.

If you want to store red onions longer, try dehydrating and tossing them into your salads – delicious! 

Can You Store Cut Onions in Water?

You can store cut onions in water, but it’s not ideal. The water can speed up the mold process. If you’re short on time, consider storing them in the freezer.

How Do I Store Peeled Onions?

If you peel an onion and put it in the fridge, it will quickly begin to soften. For this reason, it’s not recommended to store peeled onions. Either don’t peel until you’re ready to use or preserve for long-term storage using one of the methods listed above.

Now that you know how to preserve cut onions without a refrigerator, you can enjoy the fresh taste of onions all year round!