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Thread: why garlic is green in my garlic butter?

  1. #1

    why garlic is green in my garlic butter?

    please tell me why it's green and if i can fix this. not sauteed long enough? thanks

  2. #2
    Join Date
    Nov 2003
    Vancouver Island, Canada
    I don't think you can fix it. I found these reasons online:

    Garlic contains sulfur compounds which can react with copper to form copper sulfate, a blue or blue-green compound. The amount of copper needed for this reaction is very small and is frequently found in normal water supplies. Raw garlic contains an enzyme that if not inactivated by heating reacts with sulfur (in the garlic) and copper (from water or utensils) to form blue copper sulfate. The garlic is still safe to eat.

    If it is picked before it is fully mature and hasn't been properly dried it can turn and iridescent blue or green color when in the presence of acid.

    A reaction between garlic's natural sulfur content and any copper in the water or in the iron, tin or aluminum cooking utensils can sometimes change the color of garlic.

    Garlic will also turn green (develop chlorophyll) if exposed to an temperature change or is exposed to sunlight. Some people say it can be stored for 32 days at or above 70 - 80 F to prevent greening (but I'm not yet sure that is true).

    Other reasons to cause garlic to turn blue or green:

    Are you using table salt instead of canning salt? That can cause the garlic to turn blue or green. Table salt contains iodine, which discolors whatever you're pickling. Use kosher or pickling salt.
    Different varieties or growing conditions can actually produce garlic with an excess natural bluish/green pigmentation made more visible after pickling

    Don't worry, greenish-blue color changes aren't harmful and your garlic is still safe to eat. (unless you see other signs of spoilage).


    Working on a pasta sauce recipe for an upcoming issue, test cook Erika Bruce noticed that fresh garlic cloves sometimes take on an odd blue-green shade when cooked with acid (tomatoes, in this case). Under acidic conditions, isoallin, a compound found in garlic, breaks down and reacts with amino acids to produce a blue-green color. Visually, the difference between garlic cooked with and without acid can be dramatic, but a quick taste of the green garlic proved that the color doesn't affect flavor." From America's Test Kitchen Newsletter, September 2004


  3. #3
    I had an experience with blue-green garlic a couple of years ago, which sort of freaked me out so it is very interesting to read about it. I had an exchange student from Brazil staying with me and he wanted to cook a dish that was his favorite at home. He very finely chopped onions and garlic together in the food processor and sauteed them in oil in a skillet. After a few minutes they began to turn blue green. Neither he nor I had ever seen anything like it before. We threw them out and tried again and same thing happened. I've always wondered why it happened. There wasn't any acid present, but we were using a calphlon skillet. We used a wooden spoon to stir. I frequently saute onions and garlic in the same calphalon skillet and never have this happen. I wondered if the very fine mincing in the food processor, combined with the calphalon was the cause. Any thoughts?

  4. #4
    Join Date
    Dec 2000
    In transition!
    How interesting! This happened to me once about 10 years ago. There was acid present, since what I was cooking was a chicken breast marinated in a mixture garlic, lemon juice, herbs, and olive oil. The garlic in the pan turned blue when I cooked it. I called my Mom on the phone to ask what had happened, and she said, "I have no idea, DON'T eat it!" Sounds like it would have been totally safe though, and that the garlic had probably just been picked early and improperly dried. I always wondered what had happened.
    "In France, cooking is a serious art form and a national sport."
    --Julia Child

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