Why is My Garlic Blue?

As July comes to a close, I anxiously head to the Farmer’s Market to stock up on nice, new, flavourful garlic.

But, as with all things, fresh garlic eventually rots. So, I decided this was a perfect chance to try my hand at pickling garlic.

It is deceptively easy to pickle garlic, and in no time I had 4 heads ready to go. I peeled the cloves, added the vinegar , salt and some nice mustard seeds for good measure.

A couple of days went by and I checked on them. Hmmm, they are blue. Wait, what? They are blue?

I have never encountered this before. Naturally I headed to the Internet to solve the mystery, and decide whether they were fine to eat.

Low and behold it is all good. They are fine to eat and it is completely natural. Garlic can react and change colour from blue to green and even pink in some circumstances.

What the Experts Say

The colours occur when enzymes and amino acids present in garlic react with the sulfur compounds responsible for garlic’s pungent smell. The reaction causes different multipyrrole molecules to form.

According to experts, garlic contains anthocyanins, water-soluble pigments that turn blue, green or purple in an acid solution. While this colour transformation tends to occur more often with immature garlic, it can differ among cloves within the same head of garlic. The garlic flavor remains unchanged, and it is totally edible without bodily harm.

Why does this happen? That’s a good question, but there doesn’t seem to be a definitive answer. Here are some of the theories:

• Older cloves turn colour more often than fresh cloves
• Fresh cloves turn colour more often than older cloves
• Adding onions to the mix will cause it to change colour
• Any acid will cause a colour change
• Specific acids cause a colour change

No matter the cause, this has been observed by many people when combining garlic with an acid. It doesn’t seem to matter whether you are pickling, sauteing, or slow cooking.

For the record, my garlic was harvested 2 days before I pickled them. I added mustard seed, but no onions.

So if you every notice your garlic turning blue or green, and there is no other sign of spoilage, rest assured it is safe to eat. If you are serving guests, just pretend that you did it purposely.