why did my fermented garlic turn blue
FAQs fermented foods

Why Did My Fermented Garlic Turn Blue?

Why has my Fermented Garlic turned blue?

It is quite a surprise when a batch of fermented garlic turns blue. However, the good news is it’s perfectly fine to eat and not an indicator of a ferment gone wrong. I first saw this happen in a batch of honey garlic. I set up the batch to ferment just as I always have, nothing out of the ordinary. When I was examining the finished product, however, I was surprised to see the cloves of garlic ranging from an aqua-blue to a bright blue.

At first sight, I was afraid to eat it too. So, I searched the topic online and found out that many other fermenters were getting similar results and that a relatively simple explanation was involved.


is it safe to eat garlic after it turns blue during fermenting process
Why did my fermented garlic turn blue?


What causes garlic to turn green or blue during fermentation?

Garlic contains both sulfur and amino acids when they combine they can create blue pigments. Furthermore, reactions with copper (or other metals) and acid (such as that produced by the lactobacilli) can help this reaction take place and release the colors. The fermentation process sets up an acidic environment that leads to this color-producing reaction. You might have experienced this when cooking garlic with vinegar or lemon juice in a copper pan. This process can bruise the garlic, so there isn’t a uniform color change. Instead, the bruised parts undergo a more profound pigmentation release as the acid can penetrate deeper into the garlic.

Consider using the blue pigment as an indicator of a good ferment, as it shows that the desired acid environment was achieved. So, in addition to producing the fermentation that I want, this acidic condition is also keeping botulinum from forming. Blue garlic means no botulism!

Is blue garlic safe to eat?

Still not sure about whether or not blue fermented garlic is safe to eat? You can always try the smell test. Absent any sign of spoilage such as foul smell or mold, you’ve got a green light to eat it.

If it smells strong like garlic, then it is normal, if it smells bad like it turned to compost then I would say it is bad.


Hello! I’m Katie, mom, hobby fermenter, gardener, canner, and boundless experimenter. Here at Fermenters Kitchen, our team of enthusiast aims to encourage readers to embark on a fermentation journey with us, one bubbly jar at a time.