Mondo Knows Facts
Garlic can turn blue-green in acid
Sulphur compounds react with acid to form coloured pigments
Crushed garlic contains sulphur compounds that, when exposed to acid such as lemon juice or vinegar, combine into pyrrole pigments that read blue or green. The effect shows up in acidic preserves and in garlic butter left in the fridge. It is harmless and reversible in appearance, though it looks startling in a jar.
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Tags: garlic, chemistry, colour
Garlic can turn blue-green in acid: the short answers
- Where does this come from, and can I check it?
- Sulphur compounds react with acid to form coloured pigments. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a food fact?
- Yes. It sits on the Food shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.