How to Store Onions After Being Cut (Watch Video)

If a recipe only calls for half an onion what should you do with the other half?  You don’t want to throw it away.  But…how long does a cut onion last in the fridge?

Let’s find out.

I use onions when I cook all the time.

They are a culinary staple.  I always have a big bag of onions in my house ready to go.  I usually have a couple different types of onions on hand.

When a recipe calls for a specific type of onion I have to be ready!

In this blog post I want to tell you how I store fresh onions at home and in the restaurant.  

If you’re interested in how to store onions, keep reading.

How to Store Onions Before Cutting Them

When I buy onions they usually come in a mesh bag.  They are kept at room temperature in the grocery store so that’s how I store them at home. 

I keep my uncut, whole raw onions in a basket in my pantry.  I like an open basket because it provides good air circulation and that’s how you get maximum shelf life.  

Proper ventilation is pretty important because you want the onions to stay dry.  Lack of air movement could cause moisture and that’s not good for stored onions. 

How to Store Onions After Cutting Them

Cut onions are a different story. We’ve all been stuck with leftover onion. 

What should you do with it?

Once an onion is peeled, sliced or diced it should be stored in the fridge.  

Here are a few different storage methods for cut onions.

Wrap it tightly in plastic wrap.  This is good for an onion that’s been cut, but is still in one piece.  

There are so many times when you end up with half of an onion.

Put it in an airtight container like Tupperware.  I usually use a sealed container when the onion is diced into small pieces.  

In the restaurant I use the same plastic containers they use at the deli counter.  They are nice and easy to store.

An airtight plastic bag can be used to store leftover raw onions that are sliced, diced or in chunks.  

Depending on how much you need to store, you can use a regular zip-top bag.  If you have a lot to store, you can use heavy-duty freezer bags. 

If I put my cut onions in a bag or plastic wrap I toss them in the crisper drawer.  That’s the best way to prevent other items in the fridge from smelling like onions. 

The National Onion Association suggests that after onions are sliced or cut they should be stored at 40 degrees F.  That means put them in the fridge.  They say they’ll be good for 7-10 days.  

I agree with them.

Popular Types of Onions

Yellow Onion

These are the usual regular onions that you see most of the time.  They make up the majority of the onions you see in the supermarket.  

Whole yellow onions will last a long time if they are stored in the ideal conditions.  A well-ventilated place with a cool temperature is best.  

Spanish Onions are a common type of yellow onion.  I use them in sauces and sauteed dishes.  They are nice and sweet when cooked down.

Red Onion

Red Onions are known to be a mild onion.  They have a really pretty color so I like to use them in dishes that call for raw onions.  

This is usually sandwiches and salads.  

White Onion

I very rarely use white onions in my recipes.  They have a lighter flavor which is nice.  The issue with white onions is that they aren’t the best for long-term storage.  

How to Tell If An Onion Is Bad

If you have onions hanging around in the pantry for a long time it’s hard to tell if it’s gone bad sometimes. 

You’ll know you have a bad onion if it has soft spots on it when you touch it.

When you cut into it if you see brown spots it’s probably too old to use.

Also, if you see green tops sprouting out of the top of the onion it’s probably time to get rid of it.

How to Dice an Onion Like a Pro

I don’t consider myself an onion expert, but I have thousands of hours of cooking under my belt.  

And it usually involves onions.  I’ve diced a lot of onions and here’s how I do it.

When I make my tomato sauce I use fresh whole onions and I dice them up nice and small. I like when the onions disappear into the sauce. 

Dicing an onion is easy if you follow a few simple steps.

I suggest using a sharp chef knife.  

Here’s a step by step guide on how to dice an onion.

Step 1

Take your whole onion and peel off the dry outer skins.  

Step 2

Cut the onion in half from the root end to the top.  Also cut the top of the onion off.  Don’t cut off the end with the root.  Be sure to keep your fingers back to avoid getting injured.

Step 3

Peel off the outer layer of onion if it’s too hard to eat.  Remember to leave the root end intact.  That will keep the onion together while you dice it.

Step 4

Take a peeled onion half and put the cut side down on your cutting board.

Step 5

With a sharp knife, make horizontal cuts into the end of the onion half, towards the root end. 

Step 6

With the onion cut-side still down on the cutting board, slice down vertically from the top of the onion to the bottom. 

Step 7

Now cut across the onion.  You will end up with a perfectly diced onion.  Continue cutting until you get to the piece of root.  Throw the little piece of root in the trash or the compost pile.