Storing onions correctly: keeping them fresh for a long time
Storing onions sounds easy but if you want to keep them fresh for a long time, there are a few things you should note. Whether they’re in your home, in the fridge or just harvested, proper storage will dictate their taste, shelf life and quality. Did you know, for example, that it’s better to store onions in a dry and airy place rather than a cool, damp location? In this article, you’ll learn the best way to store onions, even if you don’t have a cellar. We’ll also show you how to keep onions that have already been cut fresh and which foods they shouldn’t be stored alongside.
The key points
- Whole onions should be stored in a dry, dark and airy place; only use the fridge for storing onions that have already been cut open.
- Store cut onions in glass or stainless steel containers that are airtight to keep them fresh for two to three days.
- If you don’t have a cellar: use cool, dark, well-ventilated rooms and check the onions regularly for any spoiling.
- Never store potatoes and onions together; separate storage locations will improve their shelf life.
Storing onions – list of contents
When should you keep onions in the fridge – and when shouldn’t you?
Whole onions should not be stored permanently in the fridge. You can cover onions that have been cut open and store them in the BioFresh Fruit & Vegetable safe at just above 0 °C. Otherwise it makes sense to freeze the onions.
The reason for this is that fridge environments are usually too moist, which encourages whole onions to go mouldy or soft. In addition, cold increases the breakdown of sugar in the onion, which can have a negative effect on the texture. Studies on the storage of onions show that, although certain qualities can be retained at around 4 °C, the risk of rot and microbial growth increases when the level of humidity is high. That’s why you should store whole onions in a dry, dark and airy place, outside the fridge.
How should you store onions that have been cut open?
They should be stored sealed in an airtight container in the fridge, ideally in a glass or stainless steel container with a lid. After slicing, the cut surface dries out quickly and oxidises. Closed packaging will protect against drying out, mould and any transfer of odours to other foods. In the vegetable compartment, they will generally stay fresh for two to three days.
Tips for storing onions that have been cut open
- You should protect the cut surface from the light as much as possible, for example with a lid or by turning over the half-onion. This will minimise oxidation and drying out.
- Glass or stainless steel containers are hygienic and have a neutral taste, in contrast to plastic, which can absorb odours.
- Use onions as soon as you can to enjoy a better freshness and quality of nutrients.
- Alternatively, you can also chop them up small and freeze them in portions. These portions will then last for up to three months and are ideal for use in cooking.
What should the ideal storage location for onions be?
Onions are ideally stored in a dry, dark place that is well-ventilated. Do not use any closed, damp containers as they will encourage mould to form. Instead, air circulation will ensure that the onions remain good to eat for a long time.
Onions do not like direct sunlight, heat sources such as radiators and the stove or closed, damp containers. You should instead keep them at a temperature of between 10 and 15 °C, a humidity level of below 70 percent and provide air circulation.
If you harvest your own onions, the onions then need to dry. Hang them up on a wire – they can then be stored like standard commercial onions after one to two weeks.
Tips for storing onions at home
- Separate varieties: Red and white onions age at different rates.
- Do not stack: A gap between them will prevent any pressure points and rot.
- Check them regularly: Remove any soft or mouldy onions immediately.
- Decorative and functional: Onion braids or mesh bags for hanging them up look beautiful and promote ventilation.
How can you store onions if you don’t have a cellar?
You can still store onions well even if you don’t have a cellar – ideally in a cool, dark and well-ventilated area in your home, such as in the larder or pantry.
These four factors are crucial:
- Constant temperature
- Darkness
- Good air circulation
- No heat sources nearby
For small households, it’s a good idea to purchase smaller quantities or rotate sensibly. New onions are placed at the bottom of the storage containers and older ones are used up first. Perform regular checks to see whether individual onions are soft or mouldy, and remove them immediately to prevent any spoiling. If you have space in the freezer, you can chop onions directly and freeze them in an airtight container.
Can you store potatoes and onions together?
No, potatoes and onions should never be stored together, either inside or outside the fridge.
Although both crops have similar requirements for darkness and moderate coolness, they have a large impact on each other. Onions release small amounts of ethylene, which promotes germination in potatoes and can reduce their storage time. At the same time, the moisture in the potatoes can make the onions softer and promote rot.
Store potatoes in a cool, dark place (4 to 8 °C, well-ventilated). You should separate onions in a dry, airy space. Even in homes without a cellar, it is easy to do this separation: The potatoes can be placed in the cooler part of the home, while the onions can be placed in an open basket in the kitchen. This separate storage will ensure a longer shelf life and preserve the quality of both vegetables.
