Why Does Fermenting Garlic Turn Blue (or Green)?

Have the garlic pieces in your fermentations turned blue or green? Are you worried that everything will be lost?

Don’t panic, this is normal and totally edible! This is caused by a chemical reaction between the garlic and the acid in the fermentation.

Why Does Garlic Turn Blue?

Garlic is naturally creamy white, but it can turn blue or green when exposed to an acidic environment.

Garlic can turn blue or green if it is exposed for a long time to any acidic ingredient such as lemon juice or vinegar.

The acidity causes the reorganization of the molecules in the garlic cloves. This creates polypyrroles, molecules that give garlic cloves a green or blue colour.

This reaction is not always instantaneous. It can take several hours to occur. Small pieces of garlic are more likely to turn blue, but entire cloves could also change colour.

Why Does Garlic Turn Blue During Fermentation?

Even if your recipe does not contain any acidic ingredients, your garlic cloves will likely turn blue over time.

During lacto-fermentation, the bacteria create lactic acid, providing the perfect conditions for garlic to turn blue.

Don’t be surprised if your kimchi is sprinkled with little greenish slices of garlic! This is neither mould nor a sign of failure. On the contrary, it’s a sign that the fermentation has become more acidic.

Blueing does not always happen. In any case, whether your garlic stays white or turns blue, it is perfectly normal!

Can You Eat Blue or Green Garlic?

It is safe to eat garlic that has changed colour. Blue garlic has the same texture and taste as white garlic.

In China, blue garlic is even sought after for certain traditional dishes. Among others, Laba Suan
is a garlic condiment turned green with vinegar. Jade-coloured garlic cloves are eaten during the Chinese New Year.

To prevent the garlic from turning blue, one can simply blanch the garlic cloves before fermenting them. However, part of the flavour will be lost. It is best to just get used to the unusual colour and enjoy the garlic in all its glory!

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