[Trillium]

I know this problem of discoloured garlic crops up from time to time, and I've just come across an excellent article by Bernardin, a Canadian supplier of bottling equipment. I hope it answers some questions.


"Why did my garlic turn blue-green?

Immature garlic that has not been properly cured for 2 to 4 weeks at 70°F can turn an iridescent greenish colour in pickled foods.

Garlic may also turn green when exposed to sunlight or temperature changes. Some varieties of garlic and/or growing conditions produce garlic that has an excess of natural blue/green pigmentation. This colouring becomes more evident after pickling.

Blue garlic colour changes can also be caused by a reaction between garlic's natural sulfur content and copper in water or in iron, tin or aluminum cooking utensils. Blue garlic can also result when sufficient heat is not applied to inactivate garlic's natural enzymes. i.e. pickles that are not sufficiently processed.

In most cases, greenish blue garlic colour changes are not harmful; the product remains safe to eat unless other spoilage signs are present."