Onions are arguably one of the most indispensable ingredients in the kitchen.
They come in many sizes, shapes and colors, each with their unique uses in cooking.
Being a culinary staple, people tend to buy them in bulk. Unfortunately, they often go soft or start sprouting before you get around to using them.
To avoid waste and save money, people often wonder about the best way to store onions.
This article tells you everything you need to know about how to store onions.
Regular, yellow onions are available throughout the year.
According to the National Onion Association (NOA), they are best stored in a cool, dry, dark and well-ventilated room, such as a pantry, cellar, basement or garage (1).
This is because they easily absorb moisture. If temperatures or humidity are too high, they may start to sprout or rot (2).
One study found that storing onions at 40–50°F (4–10°C) is ideal. At these temperatures, they best maintain their characteristics ().
It’s also important to ensure proper ventilation to prevent molding and rotting. An open basket, bamboo steamer, mesh bag, netted bag or even pantyhose will do.
Avoid leaving onions in plastic bags, as this may make them spoil quickly due to poor ventilation.
Furthermore, darkness helps them last longer. The lack of sunlight reduces changes in temperature and humidity, two factors that can cause them to go bad faster.
Summary It’s best to store regular onions in a cool, dry, dark and well-ventilated room. Places that may provide these conditions include a cellar, pantry, basement or garage.
Store-bought onions have papery skin, as they have been cured soon after harvesting.
Curing helps remove excess moisture, allowing them to last longer.
That’s why onions are best stored in a cool but dry, dark and well-ventilated place. These conditions ensure that they don’t absorb too much moisture or experience heat or humidity.
Storing whole onions in the fridge exposes them to cold, humid conditions. Since they absorb moisture very easily, they may become mushy and spoil faster.
However, this does not apply to peeled, sliced or diced onions. Peeled onions can be stored in the fridge for up to two weeks, while diced or sliced onions will only last for 7–10 days (4).
Summary Avoid storing whole, unpeeled onions in the fridge, as they easily absorb moisture. Doing so may cause them to become mushy and spoil faster.
Shallots are closely related to onions but have a milder and sweeter taste.
Like regular onions, shallots should be stored in a cool, dry, dark and well-ventilated place. This includes rooms such as the pantry, basement, cellar or garage.
Store shallots in a mesh bag, bamboo steamer, open basket or pantyhose to ensure they stay well ventilated. Shallots stored this way should last for up to 30 days.
Alternatively, shallots can be stored in the freezer for up to six months.
To freeze shallots, first peel off the skin and separate the cloves. Then place the peeled shallots in a resealable bag or airtight container and store them in the freezer.
Summary Shallots are closely related to onions and can be stored in a similar way, namely in a cool, dry, dark and well-ventilated place such as the pantry, cellar, basement or garage.
To ensure that your onions last as long as possible, proper storage is essential.
Here are the best ways to store them at different processing stages.
Once an onion is peeled, it should be stored in the fridge to avoid bacterial contamination.
Place it in an airtight container and ensure your fridge is set to 40°F (4°C) or below.
According to the USDA, peeled onions can last 10–14 days in the refrigerator (4).
Sliced, Cut or Diced
Sliced, cut or diced onions can be stored in the fridge for up to 10 days (4).
Simply wrap them tightly in plastic wrap or keep them in a resealable bag.
Alternatively, you can purchase pre-sliced onions at many supermarkets. Make sure to keep them refrigerated and use them before their expiration date.
For long-term use, sliced, cut or diced onions can be stored in the freezer for three to six months. They are best used in cooked dishes such as soups, stews and casseroles.
Cooked onions can be stored in the fridge for three to five days.
Simply place them in an airtight container or resealable bag within a few hours of cooking. If left outside for long periods, they may harbor bacteria.
Better yet, cooked onions can be stored in the freezer for up to three months.
Pickling is a low-cost way of extending the shelf life of your onions.
It involves storing them in a solution that hinders the growth of bacteria that typically spoil vegetables. Prepared this way, they may last up to six months (5).
To pickle onions, place peeled onions into a glass or ceramic jar filled with vinegar and a combination of salt, sugar and spices that suit your taste preferences.
Once opened, they are best kept in the refrigerator, which will help them last longer.
Summary Whole onions are best stored in a cool, dark, dry and well-ventilated room, while peeled, sliced, cut, cooked and pickled onions can be refrigerated. Onions can be frozen to further extend their shelf life, but then they are best used in cooked dishes.
People often wonder if there is a difference between spring onions and leeks.
Spring onions, also known as scallions, are simply young onions. They are harvested before the bulb fully develops and have hollow green leaves.
Leeks are a similar plant, but they do not have a bulb like spring onions. They are larger and have a crunchier texture with a milder, sweeter flavor.
Since spring onions and leeks share many similarities, they are also stored in a similar way.
If you plan on using your spring onions or leeks within a day or two, you may leave them on your counter in a jar with some water. Just make sure it’s not too hot or humid in your kitchen, or they may wilt.
However, if you intend to use them several days later, it’s best to wrap them in a slightly damp paper towel and secure the stems with a rubber band. Then place them in the crisp drawer of your fridge for up to one and a half weeks.
You can also chop and freeze spring onions and leeks to make them last several months. Make sure to store them in a resealable bag or airtight container.
Summary Spring onions and leeks share similar characteristics, which is why they can be stored similarly for up to one and a half weeks. Secure the stems with a rubber band, wrap the vegetable in a damp paper towel and place it in the crisp drawer of your fridge.
Selecting the right onions is just as important as storing them properly.
For regular, yellow onions and red onions, choose those with dry and papery skin. Moreover, the outer layer should be completely free of spotting and moisture.
They should also be firm and heavy for their size to ensure that they are juicy and not too ripe. Be careful not to choose those that have begun to sprout, as they will rot quickly.
You should also avoid onions that have a smell to them. These may be bruised or too ripe.
For spring onions, choose ones with bright white, unblemished bulbs and firm stalks. Avoid those that are wilting or have a slimy film.
Look for leeks that have lots of white and green. Their stalks should be crisp, firm and free of discoloration.
Summary Choose onions that have dry, papery skin and are free of bruises and signs of moisture. They should also be heavy for their size, firm and odorless. Spring onions should have bright white bulbs and firm stalks. Leeks should be crisp, firm and not discolored.
Onions are one of the most versatile ingredients in your kitchen.
They come in many sizes, shapes and colors, each with unique uses in cooking. To ensure onions last as long as possible, proper storage is essential.
Whole onions and shallots are best stored in a cool, dry, dark and well-ventilated room. Ideal places include the pantry, cellar, basement or garage.
Peeled onions can be stored in the fridge for 10–14 days, while sliced or cut onions can be refrigerated for 7–10 days. To keep them even longer, freeze them in a resealable bag or airtight container.
Cooked onions can be stored for three to five days in your fridge or up to three months in your freezer.
Pickled varieties can last up to six months and are best stored in the fridge after opening.
Spring onions and leeks can be left on the counter in a jar with a small amount of water for up to two days. For longer storage up to one and a half weeks, wrap them in a slightly damp paper towel and store them in the crisp drawer of your fridge.