Why Do Red Onions Turn Blue Or Green When Cooking Sometimes

Why Do Red Onions Turn Blue Or Green When Cooking Sometimes?

Cooking is an essential part of life. Some people love to cook, and others hate it, but either way, it’s a skill that we must all learn at some point.

You don’t have to be an amazing cook to achieve fantastic results, but you should know the basics.

If you’re reading this article, it’s probably clear to you by now that all foods taste, look and smell different when cooked than they do in their raw state.

It doesn’t matter if you’re working with raw veggies or frozen pizza bagels; cooking alters food.

Onions carry an array of health benefits, and if you like them, you should work them into as many of your prepared dishes as possible.

Working with red onions can bring a surprise or two, primarily by changing color during the cooking process.

If you’ve ever wondered why do red onions turn blue or green when cooking sometimes, I’ve got an answer for you!

Why Do Red Onions Turn Blue or Green When Cooking Sometimes?

When you cook them, red onions can turn blue or green due to their natural pigment, also known as anthocyanins. Anthocyanins can cause red onions to change color depending on the cooking conditions. If you’re cooking under alkaline conditions or with alkaline foods, your red onion may change its hue and take on a blue or green tinge. Remember, this is entirely normal, and your red onions are absolutely safe to consume.

Turning Red Onions Blue

It can be shocking to slice red onion, place it into a pan to saute, and then realize it’s turned blue. Let me assure you that it’s a normal part of the cooking process.

Adding a glug of olive oil to a frying pan and sauteing your red onions will leave them sort of a translucent purplish-red.

However, if you are at a point in your cooking journey where you’re experimenting with combining various foods, you’re more likely to see your red onions change color.

The Magic of Alkaline Foods

Not only are alkaline foods great for your body and overall health, but they have the potential to turn your red onions blue or bluish-green.

When integrated with alkaline foods, the anthocyanins in red onions revert to their natural blue-green hue.

If you’ve ever cooked red cabbage and spinach, an alkaline food, you’ve probably noticed that the same is true of the anthocyanins present in the cabbage.

Here are the naturally alkaline foods that will very likely turn your red onions blue when cooked together.

Green, Leafy Vegetables

Veggies like spinach, kale, and arugula are notoriously alkaline and so good for your body. They’re also delicious when sauteed with a bit of minced garlic and red onion.

Broccoli and Cauliflower

These crunchy, delicious veggies are super tasty raw, boiled, steamed, and sauteed. There’s nothing that broccoli and cauliflower can’t do, and that includes turning your red onions blue!

Citrus Fruits

Most people don’t cook citrus fruits with red onion, but slicing lemons or sauteeing red onion in the juice will most certainly give them a blue-green tinge. If you combine citrus fruits like mandarin oranges with red onion in a cold salad, you won’t see the color change.

Seaweed and Sea Salt

Two delicious, salty, alkaline foods that go perfectly with red onions. Cooking your seaweed and sea salt with some diced red onions is not only delicious, but super nutritious!

Root Vegetables

Root vegetables are very often cooked with red onions because they add plenty of flavor and a tad bit of heat to an otherwise somewhat bland veggie.

Potatoes and turnips are a fantastic pair for red onions, and if you cook them in the same pan, you’ll notice your onions turning bluish-green.

Garlic and Ginger

Onions are naturally alkaline, and if you combine them with garlic and ginger, you’ve got a tasty side dish with a whole lot of zip. Add some raw broccoli to this concoction, and you won’t be able to beat the health benefits or the taste!

Health Benefits of Red Onion

Red onions are full of health benefits that help your body function at its best, including:

  • Antibacterial benefits
  • Reduction in risk of certain cancers
  • Bone health
  • Antioxidant boost
  • Digestive and gut health

Why Do Red Onions Turn Blue or Green When Cooking Sometimes FAQs

Wondering why your food is changing color is not uncommon for those new to cooking, especially with alkaline foods.

Why are my red onions turning blue in the pan?

Red onions turn blue when you’re cooking them if they come in contact with other alkaline foods. When this contact happens, the anthocyanins that give red onions their pigment return to their natural blue hue, which can also appear green.

What foods will turn red onions blue or green?

Any alkaline food will bring the anthocyanins out of red onions and cabbage, including spinach, kale, broccoli, cauliflower, and so much more! Experimenting with these foods is a wonderful way to cook and work healthy food into your diet.


The Magical Red Onion

Not only are red onions fun to cook with, but they’re so good for you! Working more red onions and alkaline foods into your meals will allow your body to feel its best.

Remember, any time you consider a drastic diet change, make sure you consult your doctor. Until then, enjoy those incredible red onions and watch them change color before your eyes!