Are my blue tortillas mouldy? Probably not!

Are my blue tortillas mouldy? Probably not!

Short answer: it’s nature, not mould. 🌽💙

We know it can be surprising to open a pack of tortillas and see blue or blue-green patches, especially when blue isn’t a colour we expect in everyday food. We want to reassure you straight away: this is a natural colour change, not spoilage, and the tortillas are perfectly safe to eat.

What’s actually happening?

Blue and purple corn gets its colour from anthocyanins. These are natural plant pigments found in many foods you already know, like red cabbage, blueberries, blackcurrants, and purple potatoes.

Anthocyanins are sensitive little things. They respond to their environment, especially pH, which is a simple measure of how acidic or alkaline something is.

A gentle colour shift, not a fault

Anthocyanins behave a bit like a natural litmus paper:

• In acidic conditions, they tend to look red or pink
• In neutral conditions, they appear purple
• In slightly alkaline conditions, they shift towards blue

Water, including everyday tap water, can be very slightly alkaline depending on its mineral content. When blue or purple corn tortillas come into contact with moisture (during cooking, storage, or even humidity in the air), the pigments can gently shift from purple to blue.

This is the same harmless reaction used in school science experiments, where red cabbage juice changes colour to show different pH levels.

Why it can look unfamiliar

There simply isn’t much naturally blue food around, so our brains jump to the wrong conclusion. We’re used to mould being blue or green, but mould has a very different look and texture. This colour change is even, smooth, and part of the tortilla itself, not something growing on it.

Does it affect taste or quality?

No.
The flavour, texture, and nutritional value are unchanged. The tortillas haven’t gone off, and nothing has been added or altered. You’re just seeing a natural plant pigment doing what it’s always done.

In short

• The blue colour comes from natural pigments in blue corn
• It’s triggered by water and pH, not spoilage
• It’s completely safe and normal
• It’s a sign of real corn, not ultra-processed food

If you ever have questions, we’re always happy to talk tortillas. Sometimes food just likes to show a little science on the surface. ✨