Can you freeze a whole onion?
In this guide, we’ll address the query: “Can you freeze a whole onion?”. Also, we’ll explore what is the best way to freeze an onion, what are the benefits and drawbacks of freezing onions, how to safely thaw them and if frozen onions spoil in the freezer.
Can you freeze a whole onion?
Yes, it is possible to preserve whole onions in the freezer.
However, freezing whole onions is feasible for smaller types that won’t require much defrosting, though for larger, and average-sized onions, freezing them whole may be impractical.
This is because to slice or mince them, they’ll have to be thawed and that may add to the overall cooking time when the idea behind freezing onions is to preserve them in a ready-to-use state.
Briefly placing whole onions in a freezer, however, without letting them freeze, is a handy practice when looking to limit the sulfur fumes onions give off when being chopped.
What is the best way to freeze an onion?
Below, we’ll describe the outlines of the best way to freeze a normal-sized onion.
The first step is to lightly clean off the onion’s surface and peel away any layers that are already oxidized or damaged, and then chop them. They can be cut into slices finely minced, depending on the user’s preferences (2).
The idea is that frozen onion can be used immediately once taken out of the fridge, and rapidly thawed. Freezing whole onions defeats this purpose, and ergo, storing whole onions in the freezer isn’t recommended.
Once sliced or minced, the onion should all be scooped into a quality, tight-sealing freezer bag, that’ll then have as much air as possible drawn out, to prevent freezer burns (2). Sliced or chopped onions can be stored in a freezer for up to 12 months (1).
What are the benefits and drawbacks of freezing onions?
One of the benefits of freezing onions is that freezing can increase their shelf life for up to 10 to 12 months and avoid spoilage and retain their taste.
The low temperature in the freezer prevents the enzymatic activity caused by polyphenol oxidase which leads onions to deteriorate or sprout. This way you can have onions preserved all year round (1,3).
However, freezing onions might cause them to become softer and potentially mushy when thawed, since onion cell structure can be changed after freezing, resulting in a loss of stiffness (4).
Besides, long-term storage in the freezer, temperature changes, and air exposure can all cause freezer burn or off-flavors on onion; and when cooked, frozen whole onions may release more moisture, thus influencing the texture and flavor of foods (5).
How to safely thaw whole frozen onions?
To safely thaw whole frozen onions, the ideal method is to transfer the frozen onions from the freezer to the refrigerator and allow them to thaw overnight or for hours. By doing this you can maintain the quality and texture of the onions and avoid bacterial growth (6).
Another option is to thaw the frozen onions by placing them in a sealed plastic bag, submerging them in cold water and changing the water every 30 minutes to ensure a consistent thawing process (6). You can also throw the frozen onion onto a skillet for cooking and save some time.
Do frozen onions go bad in the freezer?
Generally, no. Frozen onions do not go bad in the same way as fresh onions stored at room temperature due to the method of preservation. As we mentioned, freezing onions slows down the enzymatic process preventing them from spoiling and extending their shelf life (1,2).
In this guide, we’ve addressed the query: “Can you freeze a whole onion?”. Also, we’ve explored what is the best way to freeze an onion, what are the benefits and drawbacks of freezing onions, how to safely thaw them and if frozen onions spoil in the freezer.
1. Food labeling and product dating. USDA.
2. Silva, C.L.M. Home Freezing of Fruits and Vegetables. In book: Frozen food science and technology, 2008.
3. Moon, K.M, et al. Recent Trends in Controlling the Enzymatic Browning of Fruit and Vegetable Products. Molecules. 2020;25(12):2754.
4. Van Der Sman, R.G.M. Impact of Processing Factors on Quality of Frozen Vegetables and Fruits. Food Engineering Reviews, 2020, 12, 399–420.
5. Yoo KS, Lee EJ, Patil BS. Changes in flavor precursors, pungency, and sugar content in short-day onion bulbs during 5-month storage at various temperatures or in controlled atmosphere. J Food Sci. 2012, 77(2).
6. The Big Thaw – Safe Defrosting Methods. USDA, 2013