Which Type of Onion Should You Be Using?

So you’ve got some red onions left over and no time to pop out to buy yellow ones – can you use them? Well onions aren’t all made the same, whilst it’s not the end of the world if you use the “wrong” type, for best results you’ll appreciate selecting the most appropriate type of onion for each recipe.

Firstly, how to pick a good onion?

Make sure there are no obvious bruises or softness that may indicate the onion is old. They should feel heavy, firm and not have too strong-an onion odour before you peel them.

Brown Onions

Also known as yellow onions. These are the work-horse of the onion family and for me, the type I use most frequently. They can be used in many different dishes and are fairly sweet. The longer you cook them, the sweeter they'll be.

White Onions

Cook these exactly as you would brown onions, but you'll find them less sweet and with a sharper flavour. They'll hold their texture far better on cooking than the brown onion. If you're going for a raw recipe like a salsa, these would be my preference.

Sweet Onions

Whilst these may look similar to yellow onions, they are, as the name might suggest, even sweeter. These are another good option to eat raw in things like salads.

Red Onions

These taste similar to the brown onion, but won’t become as tender. They’re great for dishes requiring vibrant colour. The flavour can be toned down by soaking them in water before use, making them great to add to colourful salsas and salads.

Shallots

These are a lot milder and great for more delicate recipes where you don’t want a strong onion flavour to take-over.
So you’ve got some red onions left over and no time to pop out to buy yellow ones – can you use them? Well onions aren’t all made the same, whilst it’s not the end of the world if you use the “wrong” type, for best results you’ll appreciate selecting the most appropriate type of onion for each recipe.

Firstly, how to pick a good onion?

Make sure there are no obvious bruises or softness that may indicate the onion is old. They should feel heavy, firm and not have too strong-an onion odour before you peel them.

Brown Onions

Also known as yellow onions. These are the work-horse of the onion family and for me, the type I use most frequently. They can be used in many different dishes and are fairly sweet. The longer you cook them, the sweeter they'll be.

White Onions

Cook these exactly as you would brown onions, but you'll find them less sweet and with a sharper flavour. They'll hold their texture far better on cooking than the brown onion. If you're going for a raw recipe like a salsa, these would be my preference.

Sweet Onions

Whilst these may look similar to yellow onions, they are, as the name might suggest, even sweeter. These are another good option to eat raw in things like salads.

Red Onions

These taste similar to the brown onion, but won’t become as tender. They’re great for dishes requiring vibrant colour. The flavour can be toned down by soaking them in water before use, making them great to add to colourful salsas and salads.

Shallots

These are a lot milder and great for more delicate recipes where you don’t want a strong onion flavour to take-over.

What type on onions do you use in which dishes? Do you eat them raw?

Storage tips for keeping onions fresh

Once you've picked the perfect onion, knowing how to store it properly can make all the difference. Whole onions should be kept in a cool, dark, and well-ventilated place. Avoid storing them near potatoes, as both release moisture and gases that can lead to spoilage.

If you've only used half an onion, wrap the unused portion tightly in cling film or store in an airtight glass container and refrigerate. It’s best to use it within a few days to maintain freshness and avoid odours tainting other foods in your fridge.

Onions and cooking techniques

How you cook an onion can dramatically change the flavour profile of your dish. For example:

• Caramelising: Slowly cooking sliced onions in a bit of fat over low heat releases their natural sugars, resulting in a sweet, deeply flavoured addition to meats or stews.
• Sautéing: A quicker cooking method, sautéed onions add flavour depth to stir-fries, omelettes, and sauces.
• Roasting: Roasting thick wedges of onion brings out their sweetness and adds a lovely charred edge that works well in tray bakes or served alongside roast meat.

The nutritional case for onions

Aside from their culinary versatility, onions also offer an impressive nutritional profile. They are a good source of:

• Vitamin C – for immune health and collagen production
• Folate – supporting cell function and tissue growth
• Antioxidants like quercetin – which may help reduce inflammation

Including onions in your meals is an easy and inexpensive way to boost nutrient density while adding heaps of flavour.

Raw vs cooked onions: pros and cons

Eating onions raw preserves more of their vitamins and enzymes, but they also have a stronger flavour and may be difficult for some people to digest. If you’re using them raw in salads or dressings, choose sweet or red onions and slice them thinly.

Cooked onions, on the other hand, become much milder and sweeter as their sugars break down. They also lose some of their nutritional content, but many people find them easier on the digestive system.

Experimenting with less common varieties

Beyond the standard supermarket types, there are many lesser-known onions worth exploring:

• Spring onions (scallions): Mild and slightly sweet, perfect for garnishing soups and stir-fries.
• Chives: Delicate, grassy flavour, ideal in creamy dressings or scrambled eggs.
• Pearl onions: Small and sweet, often used in stews or pickled.

These varieties can introduce new layers of flavour to your dishes and are well worth trying, especially if you shop at farmers markets or grow your own.

Why onions are Paleo-friendly

Onions are completely compatible with a Paleo lifestyle. They’re naturally low in calories, high in antioxidants, and free from processing. Better still, they pair beautifully with meat, vegetables, and healthy fats — making them a staple in countless Paleo recipes.

Their prebiotic fibre content also feeds beneficial gut bacteria, promoting better digestive health and potentially improving immune function. So next time you’re cooking up a Paleo feast, don’t be shy with the onions.

Final thoughts: make onions work for your cooking style

Whether you're making a rich stew, a fresh salad, or a spicy stir-fry, there’s an onion that’s perfect for the job. Knowing the differences between each type — and how best to prepare and store them — will only elevate your home cooking.

So next time you reach for an onion, make it an intentional choice. Your tastebuds (and your body) will thank you.

What type on onions do you use in which dishes? Do you eat them raw?