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Jan 15, 2012 12:47 PM

What would make my wet curry turn blue?

Ok I decided to finally try the wet curry recipe in the Indian Slow Cooker cook book. It's basically onions, garlic, fresh ginger, turmeric, tomatoes, salt and oil. I used coconut oil and canned diced tomatoes because I didn't have enough fresh ones ( it called for fresh) and I was too lazy to go to the store.

Lazy part number two. Instead of dicing 3 pounds of onions I basically quartered them and them pureed them in the food processor with the garlic. It was going to be pureed after cooking for 4 hours anyway and hey, it works in my tandoori recipe.

So I put everything in the slow cooker and it says to cook on high which I do. But when I checked it about an hour in it has spots that look blue and others that look green. I stir it up and see what the heck is happening. More blue appears and then it settles into an odd yellow green color.

Now it's been 4 hours and I just pureed it with the immersion blender to get to smooth as it says in the recipes since I had a few onion pieces left and the tomatoes to get smooth.

It looks ok now, kind of a medium brown. I've never cooked this particular recipe but I've made lots of curries from scratch and never seen this happen.

Is it some weird chemical reaction? DH told me he washed the crock with ajax ( head slap) to try and get some stains off but he says he rinsed it well, and hey it looked totally white and clean when I checked it before adding the food.

My ginger was kind of slimy from being in the fridge but it felt fine after rinsing and I peeled it under running water before chopping. This is what I get for being lazy lol.

I guess I'll be the guinea pig and see if it makes me sick before I let the rest of the family try it LOL.

Anyone have any idea why it would turn blue and green?

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  1. Maybe the Ajax looks white when dry... turns blue/green when wet?

    1. I thought it might have something to do with the garlic or onions maybe the sulfur content. Anyway a google search came up with this

      The discoloration is due to pigments that form between sulfur compounds in garlic and amino acids. When the garlic tissue is disrupted, as happens in processing, an enzyme is liberated and reacts with it to form thiosulfinates compounds that then react with the natural amino acids in the garlic to form blue pigments. The age of garlic determines how much isoalliin there is in the first place, and the nature of the processing determines how much enzyme is liberated.

      1. Pureed onions with garlic turn blue. It's a chemical reaction - I forget exactly what, but I'm sure it's Googleable.

        1. That happens sometimes when I am frying onion puree on stove top. If you just keep on cooking, it will turn the desired golden brown. It can happen with just onions, no need for garlic or ginger to be in the medley yet, but garlic will make the color more intense.

          1. i wouldn't take ginger out of the running either - I was just grating fresh ginger root on a ceramic grater and was surprised by a blue/green/gray hue. Tasted fine, seemed fresh, but was blue. Used it anyway to no ill effect in a dipping sauce. Dipping sauce did have grated garlic as well, but garlic was grated after the blue ginger. (Hmmm...non sequitur, but is that how Ming Tsai's restaurant name came into being?)

            Oddly, I had just had another blue tinge experience hours before, while making applesauce. Ingredients: apples from the family tree (frozen), clover honey, and a dash of vanilla extract. Cooked in an enameled cast iron pot. Blue-tinged spatters accumulated on the pot sides above the level of the simmering applesauce. (I use no scouring cleansers other than baking soda. Can baking soda do it?) I relate this not to threadjack, but because it was so odd to have two food blue-ings on the same day, with nothing obvious in common!

            I'm really curious about the situations in which this seems inconsistent, as I've most times had the same ingredients *not* turn blue.