How to best Store Onions to prevent spoilage

Onion is the staple vegetable in most households. Today's post is about how to store onions. We will dive deep into the various storage concerns regarding Onions. I would try to address all the issues related to the storage and spoilage of onions at home.

Estimated reading time: 7 minutes

Onion ( Allium sepa), is the key vegetable in almost all the cuisines. Be it soups, stews, curries, salads, pasta sauces, or anything else,  nothing is complete without onions.

In my Indian kitchen, onions are the base for every curry or masala recipe. Almost everything savory that I make has some type of Onion.

There are various types of onions. They have different colors, shapes, size, flavor and pungency. 

Few that I happen to know are Sweet onions, Pearl Onions, Cippolini onions, White onions, Yellow onions, Red onions, and Spring Onions.

A few varieties spoil faster than the others. The sweet onions have very high moisture and spoil faster.

But the bottom line is that all Onions have about 89% water, which is the main reason that it spoils over prolonged storage.

In this post I will try to answer following questions:

How to store a large batch of whole onions?

If you do not buy big batches of onions, the kitchen counters are the best place to store them. Place them in a brown paper bag with holes, or a mesh bag or an open basket.

How long do onions store well at room temperature?

In our Urban households, Cured Whole Onions stored in a cold, dry and dark place would easily store well for 3-4 months.

 Back home we grow onions and store the cured onions in a specialized dark celler, by spreading them on wooden boards. They keep well for about 7-8 months. Off couse,  they need regular inspection to find and remove the ones going bad. Usually after 7-8 months, onions start to show some sprouting signs.

 So, if you are storing onions at ideal conditions, they will even last 7-8 months.

Should you refrigerate whole onions?

Refrigerator is never an ideal place to store Onions. They will spoil faster in the fridge. Also, their texture will not be crispy.

Storing whole onions in the fridge is a recipe for spoilage.

Whereas peeled and chopped onions should be stored in refrigerators.

How to store peeled and chopped onions?

For storing peeled or chopped onions, it is important that we realize that onions have nutrients that get oxidized post cutting or peeling. And not to forget, they will fill your kitchen with the pungent odor. So they should always be stored in an airtight container( avoid exposure to oxygen).

• You can store the peeled onions in an airtight glass container for a day or two at room temperature.
  
• If you intend to store for longer, consider placing the container in the refrigerator. It can keep well for almost a week in the refrigerator.

• Chopped onions can be frozen for 3-4 months. Store them in a zip-locked freezer-safe bag and cover it with aluminum foil, or use an airtight container. This is the best way to extend the shelf life of chopped onions.

If you are planning to store the chopped or peeled onions for a week in the refrigerator, choose a glass airtight container. The plastic containers will absorb the pungent odor of the onions and transfer them to the other food items in the fridge.

How should you store Cooked onions?

• Cooked onions can be kept at room temperature for a day or two in an airtight container.
• For extended life, you can refrigerate them for 3-4 days. But make sure to put them in an airtight container, preferably glass.

• Cooked onions will last 8-9 months when frozen. Store them in an airtight container or a freezer safe ziplocked bag. Do not forget to wrap the bag in aluminum foil.

Ways to extend the shelf life of onions beyond 12 months

1. Canning of Onions

Only way to increase the shelf life of onions beyond 12 months is canning. Being low acid foods, onions need to be pressure canned. Though I have no experience with that, but canned onions will last 3-5 years.

2. Picking in oil/vinegar

Also, the Indian way of picking onions in oil and spices, ensures it stays well for more than a year. Back in India, my grandma prepares onion pickles by roasting them in oil and then pickles them in vinegar and spices. It stays well for years. But it is so yum, that it never lasts that long. Hopefully, I will get to share the recipe someday.

How to store Spring onions/ Spring Greens:

Unlike mature onions, spring onions are best stored in a refrigerator in a plastic bag. Place them in the crisper drawer of your refrigerator. They will refrigerate well for 10-12 days.

How to tell if onions are spoiling/ Spoiled?

• Well, if an onion has gone bad in your kitchen, anybody could tell it by the smell.
• But in initial stages of spoilage, it is not that smelly. In that case, one should inspect them visually for any bruises or spoilage signs on the surface of onions.
• Watery patches on the outer skins are evident signs of spoilage.
• But sometimes an onion start to go bad from its inner layers and from the outer surface you cannot detect it. In such cases by pressing the onions with your hands you can tell if it is firm or not. And if it does not feel firm, there is a possibility of a rot in some inner layer.

What is that black mold on my onions?

• The typical black mold on the surface of onions is Aspergillus Niger. Though it is not that harmful, can cause serious sickness to some people. It is not safe to consume.
  But, if the mold is just superficial, you can just cut and discard the affected area and wash the rest of the onion well before using it.

Fun Fact : Onion skins can be boiled to make an orange-brown dye.

Now, let us move towards the brown brother. How about storing onions and potatoes together?

Can we store Onions and Potatoes together?

• Never keep onions with potatoes, if storing in a closed space.
• Store onions and potatoes in open spaces, the kitchen counters, well-ventilated pantry spaces, mesh baskets, wire racks, etc. and preferably away from each other.
  

If you found this post helpful, do let me know in the comments below.