Canned onions are a real boon to the home cook and a must-have for the Doomsday prepper.
And is it really any wonder? They don’t cost much to stock up on, they are carried by virtually every dollar store and supermarket, and, once opened, the onions can be incorporated into a variety of delicious meals to feed even the hungriest of eaters.
From a food storage perspective, canned onions are attractive because they are shelf-stable. In other words, they don’t need to be refrigerated, and as long as you store them properly—which we’ll get to in a moment—they have an almost unlimited shelf life.
And yet, no food lasts forever. Even canned foods, which stay safe to eat for decades, will eventually lose their flavor profile and nutritional value with the passage of time.
So let’s talk about how long canned onions last (and how to store them).
How Long Do Canned Onions Last?
Canning is a great way to preserve onions along with most of their nutritional value for an extended period of time. It’s also economical, as canned onions can be safely stored without the need for refrigeration or freezing.
Exactly how long this period is depends on the preservation method. As a rule of thumb, commercially canned foods stay safe to eat for longer than home-canned foods do because the canning process is tightly controlled and the containers—tin cans, glass jars with lids, and Mylar bags—are highly reliable.
Properly stored, commercially canned onions will stay safe to eat indefinitely. But the canned onions will retain their best quality for only up to 2-3 years.
After that, they will start to lose their flavor profile and vitamin content. Their protein, carbohydrate, and mineral content, however, will remain the same.1”How Long Can You Keep Canned Goods,” USDA, https://ask.usda.gov/s/article/How-long-can-you-keep-canned-goods
Home canned onions will keep their best quality for 1 year and should be used up within 2 years of canning.2Storing Canned Goods, Preserve The Harvest extension, Utah State University, https://extension.usu.edu/preserve-the-harvest/research/storing-canned-goods
How to Store Canned Onions
Store canned onions in a cool, dry, and dark place—away from sources of heat, excess moisture, and direct sunlight. Research has shown that the ideal storage temperature for canned foods is from 40 to 70 degrees Fahrenheit (from 4 to 21 degrees Celcius).3Green R., D.J.Rose, L.V.Ogden, O.A.Pike. “Effects of long-term storage on quality of retail-packaged wheat.” Journal of Food Science
The best places to store canned onions in the home are in a dark cupboard in the kitchen, on the shelving of the pantry, in an unheated basement, or in a low-humidity root cellar. If you don’t have space for them in these areas, you can also store them in the garage or attic (although the storage temperature there will likely be higher than ideal).
No matter where you keep your canned onions, make sure to store the cans off of the floor. Otherwise, moisture can build up underneath them and cause the cans to rust, making their edibility impossible to determine.
Keep canned onions far away from the stove, the fridge, the freezer, the dryer, an AC unit, a heater, or any pipes. Don’t put them on the windowsill, especially if they’re preserved in glass jars or any other sunlit areas in your home.
When storing commercially canned onions, make sure that the best-by date is clearly visible on the can. (Hint: It’s usually printed on the lid or the bottom of the can.)
If it isn’t visible, then write down the date you purchased the onions from the supermarket on a label.
When storing onions that you canned yourself, label the date of canning on the jar’s lid with a marker.
Can You Eat Canned Onions Past Their Expiration Date?
As long as the onions were commercially canned and you stored them properly—to put it simply, in a cool, dry, and dark place—food safety experts claim that they will stay safe to eat indefinitely.4”Tips on Whether to Keep Canned Food,” Michigan State University Extension, https://www.canr.msu.edu/news/tips_on_whether_to_keep_canned_food
This means that, technically, you can eat canned onions past their expiration date, but there are a few rules to hoe by.
To get the best quality in terms of flavor profile and nutritional value, consume the canned onions within 1-2 years of when you unpacked them from the grocery bags or canned them yourself.
When it comes to canned goods, food safety should be taken seriously.
Improper canning, whether at the factory or at home, can lead to the growth of Clostridium botulinum, a type of bacteria that produces a neurotoxic protein that can cause the severe (and deadly) food poisoning known as botulism.5”Are My Old Cans Still Safe to Eat?,” AnswerLine, Iowa State University Extension, https://blogs.extension.iastate.edu/answerline/2014/09/29/are-my-old-cans-still-safe-to-eat/
Before eating or cooking with canned onions, inspect the cans to check for bulging, swelling, corrosion and rust and look for signs of cracks and broken seals on jars. If the vacuum seal is broken, throw the onions away. Disease-causing bacteria can get in and render them unsafe to eat.
Discard badly dented cans or jars with bulging or loose lids. And don’t try to eat the onions if you hear and see them fizzing, spurting, or foaming after opening.
Even after opening, trust your senses and apply common sense. If the onions look weird and smell off, don’t eat them.
Can Canned Onions Freeze?
Don’t freeze canned onions in their original container or accidentally allow them to freeze when stored in the trunk of your car or in an unheated basement during the months of winter.
Freezing causes the onions in the can or jar to swell, degrades their texture, and may lead to rusty cans that burst or jars with broken seals that invite disease-causing bacteria.
To freeze onions, first transfer them from the can or jar that they were canned in to a freezer bag or freezer-safe container. Frozen food stays safe to eat indefinitely, but it will eventually dry out and lose its best quality.