Why Do Onions Last So Long?

When you peel an onion, you may wonder why onions have such a long shelf life. After all, severing the top of the bulb causes it to disintegrate. Why Do Onions Last So Long?

Because their cells are strong and rich in pectins, onions keep longer than most other vegetables.

Pectin is a substance that gives foods like apples, oranges, and tomatoes their structure. Pectin gives onions their firmness and keeps them from disintegrating.

Let’s delve deeper and determine why onions are so long-lasting. Read the next article to learn more about onions.

Why onions last so long matter?

First and foremost, it can help you to better plan your meals and grocery shopping. If you know that onions have a long shelf life, you can feel more confident about buying a larger quantity at once without worrying about them going bad before you have a chance to use them all.

This can help to save time and money, as you can purchase onions in bulk and store them for a longer period of time.

In addition to helping with meal planning and grocery shopping, understanding the factors that contribute to the long shelf life of onions can also help you to properly store them in order to make them last as long as possible.

By following best practices for storing onions, such as keeping them in a cool, dry place with good air circulation and away from other produce, you can ensure that your onions stay fresh for as long as possible.

Finally, understanding why onions last so long can also be of interest from a culinary perspective. Onions are a staple ingredient in many dishes, and being able to use them over a longer period of time can give you more flexibility in your cooking.

This can be especially useful if you enjoy cooking with fresh ingredients and want to be able to use them for an extended period of time.

Read Also: Why Do You Rub an Onion on the Grill?

Reasons why onion lasts so long?

Here are a few major reasons why onions last so long:

Onions Have a Thick, Dry Skin

One reason that onions last so long is their thick, dry skin. This outer layer helps to protect the onion from moisture and pests, which are two of the main factors that can cause onions to spoil.

The skin also helps to regulate the onion’s moisture levels, ensuring that it doesn’t get too wet or too dry. As a result, onions can be stored in a cool, dry place for extended periods of time without going bad.

Onions are Naturally Low in Moisture

In addition to their thick skin, onions are naturally low in moisture. This means that they don’t have much water in them, to begin with, so there’s less chance for bacteria and other microbes to grow. As a result, onions can last for weeks or even months without going bad.

Onions are High in Sulfur Compounds

Another reason that onions last so long is their high sulfur content. Sulfur compounds, such as sulfoxides and sulfides, are responsible for the pungent smell and flavor of onions.

These compounds also have antimicrobial properties, which means that they can help to kill off bacteria and other microbes that can cause spoilage. As a result, onions can be stored for longer periods of time without going bad.

Proper Storage is Key

While onions are naturally resistant to spoilage, it’s still important to store them properly to ensure that they last as long as possible. Here are a few tips for storing onions:

  • Keep them in a cool, dry place: As mentioned earlier, onions prefer a cool, dry environment. This means that they should be stored in a pantry or another cool, dry place, rather than in the refrigerator or a damp basement.
  • Avoid placing them near other produce: Some fruits and vegetables, such as apples and potatoes, give off ethylene gas as they ripen. This gas can cause onions to spoil faster, so it’s best to store them separately.
  • Don’t cut them until you’re ready to use them: If you cut an onion and then store it, it will start to go bad more quickly. To keep your onions fresh for as long as possible, wait until you’re ready to use them before cutting them open.
Onion storage

Onions Can be Frozen for Long-Term Storage

If you have a large batch of onions that you’re not sure you’ll be able to use before they go bad, you can always freeze them for long-term storage.

To freeze onions, simply peel and chop them into small pieces, then place them in an airtight container or freezer bag. When you’re ready to use them, simply thaw them in the refrigerator or use them while they’re still frozen.

Read Also: Why You Soak Onion Rings in Buttermilk?


Onions are able to last for long periods of time due to their low moisture content and high sulfur content. The low moisture content prevents the growth of bacteria and fungi, while the high sulfur content acts as a natural preservative. Additionally, onions have a thick, protective outer layer that helps to keep out contaminants.

All of these factors contribute to the longevity of onions and make them a staple in many kitchens around the world. So next time you notice that your onions are still fresh and firm weeks or even months after you’ve purchased them, you’ll know why!

FAQs | Why do onions last so long?

Here are a few FAQs related to why do onions last so long?:

Why Do Onions Last So Long Compared To Other Vegetables?

Onions have a high level of sulfur compounds, which helps to preserve them and prevent spoilage. The skin of the onion also provides a natural protective barrier against bacteria and other contaminants.

Can Onions Go Bad?

If so, how can I tell if an onion has gone bad? Onions can go bad, but it takes a long time for them to do so.
An onion that has started to rot will have a soft, mushy texture and may have visible mold on the surface. The smell of the onion may also be strong and unpleasant.

How Should I Store Onions To Make Them Last As Long As Possible?

To make onions last as long as possible, store them in a cool, dry place with good air circulation. Avoid storing onions in a damp or humid environment, as this can cause them to rot more quickly.
It is also a good idea to keep onions away from other produce, as they can release gases that can cause other foods to spoil faster.

Can I Freeze Onions To Make Them Last Longer?

Yes, you can freeze onions to make them last longer. To freeze onions, first peel and chop them into the desired size.
Place the chopped onions in an airtight container or freezer bag, and store them in the freezer. Frozen onions will last for several months in the freezer.

Is It Safe To Eat An Onion That Has Been Stored For A Long Time?

As long as the onion has been stored in a cool, dry place and has not developed any visible signs of spoilage, it is generally safe to eat.
However, onions that have been stored for an extended period of time may not be as fresh and flavorful as more recently harvested onions.