Why Do Dehydrated Onions Turn Pink? (How to Fix It)

When dehydrating onions, you might notice they turn pink! Here’s why, how to fix it, and why it’s nothing to worry about!

There’s nothing like preparing a ton of onions for the dehydrator to make dried minced onions or create your own onion powder and take out a tray to find that many of your onions have turned pink.

You think it’s ruined.

Good news: It’s not!

Ways Onions May Change Color

Depending on the kind of onion you have and the heating source that comes with it, onions might turn one of these colors:

Pink

Onions turn pink from either higher sugar content or from cells bruised through using a food processor or a very dull knife to dice.

This is not the same thing as pinking onions from pickling.

Brown

A higher sugar content can cause onions to caramelize. This isn’t the same as burning. It can give the onions a ‘toasty’ flavor.

Green

This usually occurs in red onions, or cabbage) that contain anthocyanin, which are colored water-soluble pigments belonging to the phenolic group (source). These may be affected by heat and chemicals like aluminum, iron, or tin.

A Cosori dehydrator tray of dehydrated onions that have turned pink.

Are Onions that Have Turned Pink Safe to Eat?

The critical thing to remember about all of these reactions is:

Your onions are safe to eat.

Can You Stop Onions from Changing Color?

For Pink Onions:

Blanch – blanching for a minute or two can help reduce the sugar content. If you want to learn more, read about how to blanch vegetables for dehydrating.
Slice, chop, or use a vegetable chopper to reduce bruising of the cell structure of the onions.
Use a sharp knife. Not only are dull knives more dangerous for you as a user, but they can bruise the cells of the onions more by crushing them instead of slicing through them.

For Brown Onions

Because this is the caramelization of the sugars, the best way to prevent it is to turn down the temperature of your food dehydrator. However, remember that a little caramelization (also known as the Mallard reaction that gives steak that great crust) gives your dried onions a little more depth of flavor! It’s also why we love drying caramelized onions (these are more technically stewed).
If you have a stackable dehydrator, rotate the trays every 4-5 hours to keep foods away from the close heat.