Decoding Onion Freshness: Signs to Watch For

Using fresh onions is essential to get as much of the peppery, spicy flavors as you can, along with the crunchy, tender texture. However, if you’re new to cooking, you might find it a bit challenging when to call a bad or good onion.

This in-depth guide will help ensure you get the most from this aromatic flavoring!

And, if you want to test the theory, you can use your fresh onions in my Cucumber And Onion Salad!

Best Onion guide

How To Tell If An Onion Is Bad

Today we will get right to the point. There are MANY different signs that onion may not be good anymore. And what makes it tricky is that not all these signs appear simultaneously or even every time!

In one case, you may see discoloration on the flesh. In another, you may see the inside discoloring. There are really a lot of variables. And usually, you will need to look out for a couple of signs of bad onions.


This is one of the best and most accurate ways to know if your onion is bad. Good onions have a firm texture. So if you start noticing pliable, mushy, soft, or soggy onions, then that only means that you no longer have good ones. In the same way, when buying ingredients, avoid onions that feel tender.

Even if the onion doesn’t show any mold or rot, the softer texture means the flesh has started to break down. And with onions, the risk is that you ingest harmful chemicals once this happens. These can cause mild stomach aches, nausea, and even vomiting.

Stinky Pungent Odor

If you have ever smelled a rotting or bad onion, you’ll never forget it, especially if you have a large bag of them. Onions can get extremely putrid when they go bad, and doing a simple sniff test will tell you just that.

If you start noticing any sour, rancid, sulphuric odors from your batch of onions, you need to inspect them to find the bad ones in the batch. If you’re not sure about the smell, try cutting one and smelling half an onion to clarify the smell.

If you don’t get rid of it as soon as possible, it can quickly cause the other onions or produce to spoil. This is a definitive way how to tell that you have a bad onion.


The slight powdery black dust or brown spots that you often find on the exterior hard shell of the onion is actually a type of mold. It’s not good. It doesn’t show that the onion has spoiled, but it definitely doesn’t indicate that the onion is super fresh.

If you see black powder on the brown skin of the onion, look out for other signs of spoilage.

If there are no other signs of spoilage, you can always try to peel the papery skin to remove the black mold. If there is any black mold on the actual flesh of the onion (the fresh parts), rinse it off.

As long as the mold isn’t accompanied by rotten areas or other types of mold, it should be fine to eat.


Here’s the thing: discoloration is one thing, and mold is another. The outside of the onion is a thin, hard, crisp skin. This skin is usually uniformly brown or purple in color. At least, the fresher the onion is, the more uniform in color the skin will be.

A good onion also usually has a light brown, bright, saturated color. The older it gets, the darker this color gets.

So, how do you tell if an onion is bad? Now, as the onion spoils, the skin may also become black. This isn’t a good sign.

If you see any discoloration inside the onion (on the fresh fleshy parts), you should take a closer look for other signs of spoilage.

Green onions aren’t fresh at all. And, they aren’t “under-ripe.” They are a sign that the onions have aged too long and that they are starting to go off.


Sprouting doesn’t make onions inedible. A sprouted onion means that it is no longer fresh and that its nutrients, texture, and flavor will be different.

You can definitely still eat sprouted onions but be sure to remove all of these areas, including the inside layers that are now the start of leaves or roots.

Bad Onions

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How To Tell If Red Onion Is Bad

Red onions have exactly the same signs of spoilage as white onions do. The biggest difference is in the discoloration aspect. When red onions start going off, the bright, saturated purple color becomes faded and gets a bunch of different shades.

Red onions are also more prone to show black and brown spots and mushy areas if they are far gone.

How To Tell If An Onion is Bad

How Long Does Onion Last?

How long onions last depends on the type of onions you have, if they are whole raw onions, chopped onions, or spring onions, and if they are under proper storage settings. I’ll tell you the basic facts you need to know in this section.

Whole fresh onions

Whole onions last several weeks, about 2-3 months, when stored in a cool, dry place away from direct sunlight. It’s not always wise to store fresh onions in the refrigerator as too much moisture attracts molds.

Sweet onions

Sweet onions have a higher water content, making them more susceptible to spoilage, and have a shorter shelf life of 2-3 weeks in a cool and dry place. The shelf life of long onions, like storage onions, depends on the temperature but has almost the same shelf life as sweet onions.

Chopped onions

Let’s say you have leftover ingredients and want to store cut onions. Obviously, chopped onions have a shorter shelf life than whole onions. Chopped or cut onion lasts about 2-3 days in the pantry at room temperature, but you can always refrigerate them to last up to 10 days.

A good way to store chopped onions is by placing them in a freezer bag or resealable bag and store at the coldest part of the refrigerator. Just make sure to release moisture and remove air circulation to avoid getting them mushy. You can also place them in an airtight container, preferably a glass one if you don’t have a freezer bag.

Spring onions

Unlike whole onions, spring onions or fresh alliums prefer more moisture and last long in very cool temperatures. Spring onions last two weeks in the crisp drawer in your refrigerator. Keeping them in damp paper towels than plastic wrap helps them stay fresh for longer. You can also stuff the entire grocery bag in the crisp drawer if you’re in a hurry.

Spring onions lose moisture quickly when stored at room temperature, so be sure only to take them out when you’re ready to use them.

How To Properly Store Onions To Prevent Them From Spoiling

There are many different ways to properly store onions. And it mainly depends on how old they already are.

While onions like cool dry places, they shouldn’t be stored inside the refrigerator. The moisture inside the fridge gives the onions moist spots and softens their texture extremely quickly.

The only exception to this rule is if you live in a very humid and very warm country. This speeds up the sprouting process, which makes the onion unusable after a while. In the same way that moisture from the fridge softens the onions’ texture, so will an extremely humid environment.

So, it’s better to store onions in the refrigerator IF you are using them within a couple of days. Ideally, keeping onions in a cool, dry, and dark place that is well-ventilated is the best way to store them. It should not be in direct contact with any light, moisture, or heat.

And finally, don’t store potatoes and onions next to each other. They actually help each other spoil quicker. The gas coming from onions also hastens the sprouting of potatoes, which means they will have a shorter shelf life.

Fresh onions, like leeks, chives, and green onions, can be stored inside the fridge. These are more herbaceous than vegetable-like.

How To Tell If An Onion is Bad

Can You Freeze Onions?

Yes, you can store onions in the freezer using a few methods for long term storage. However, if you plan on freezing fresh onions, keep in mind that their texture will NEVER be the same again.

Like with all fresh produce, once you thaw the ingredients, ice crystals completely ruin the onions’ texture. This also simultaneously causes some flavor, aromas, and, of course, nutrients to leech out.

So, don’t expect to use the frozen, thawed onions in a fresh salad, salsa or to make crunchy pickles. It’s best to use frozen onions in stews, soups, sauces, and cooked toppings.

You can also freeze pickled onions. Again, they will lose their crunch. But it’s a surefire way to extend their shelf life.

Can You Freeze Onions

Is Old Onion Still Usable?

If you have been storing onions for quite some time, you may start wondering if it’s still viable for recipes, and the answer is yes! As long as you don’t notice any white mold, dark spots, or mushy spots, you’re good to go.

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