Now that the weather is getting colder many people will be making their favourite stews, soups or other cosy dishes - and one staple ingredient in most hearty recipes is onions. 

Nothing is worse than reaching for a vegetable only to discover it has spoiled before its expiry date, but you can help make onions last longer stored away from the fridge and in the proper spot in the kitchen. 

The best place to store whole onions

Chuck Sillari, a cook and founder of Mortadella Head has shared he keeps his onions in a pantry but you can also keep them anywhere dark, cool and airy. 

He said: “I keep my uncut, whole raw onions in a basket in my pantry.  I like an open basket because it provides good air circulation and that’s how you get maximum shelf life.  

“Proper ventilation is pretty important because you want the onions to stay dry.  Lack of air movement could cause moisture and that’s not good for stored onions.”

The key to ensuring onions stay fresh is to keep them away from water as storing them in an enclosed space will allow moisture to collect which will cause the onions to become mouldy. 

Warmth and light will also cause onions to bigger sprouting which will cause onions to turn green and develop a bitter taste which is why is it important to keep them someplace dark. 

Keep whole onions away from the fridge as it is too cold and humid for them to stay fresh, and instead, store them at room temperature in a cupboard or drawer if you do not have a pantry. 

When stored in a cool, dark and well-ventilated environment, onions can stay fresh for one or two months longer. 

The best way to store cut onions 

Once an onion has been cut then it will likely only last a few days as it will begin to lose lots of moisture at a rapid pace, and can become a hot spot for bacteria if not stored correctly. 

While a whole onion needs plenty of air and is kept out of the cold to stay fresh, the opposite is true for sliced onions as you need to limit how much air is it exposed to. 

Chuck said: “Once an onion is peeled, sliced or diced it should be stored in the fridge… wrap it tightly in plastic wrap.”

Keeping sliced onions in an airtight environment limits the amount of airborne bacteria which can get onto the surface so they stay fresher for much longer. 

You can also place sliced onions in a container with a lid or a sandwich bag if you would prefer as both will also reduce air exposure. 

Sliced onions are best kept in the fridge as cooler temperatures limit the growth of bacteria so the onion pieces do not become mouldy. 

Chuck said: “If I put my cut onions in a bag or plastic wrap I toss them in the crisper drawer.  That’s the best way to prevent other items in the fridge from smelling like onions.”

When sliced onions are sealed and kept in the fridge they typically can keep fresh for seven to 10 days longer.