[Sca-cooks] Weird Kitchen Science: Fascinating color-shift phemonenon...

[Phil Troy / G. Tacitus Adamantius]

Hullo, the list!

Okay, I've seen this happen before, but never to this extent. For 
reasons too complex to go into here, I'm making a Myanmar-style 
(a.k.a. Burmese) curry paste / sauce in quantity, starting with about 
twelve pounds of blender-pureed Bermuda onions. When you work with 
one or two such onions, yes, you do get a bit of a bluish-green color 
shift when the onions are blenderized, and then thrown into the pan 
to caramelize. The basis for most Burmese curries seems to be about 
ten parts onion, two parts garlic, and one part ginger, all pureed 
together and cooked down and caramelized with plenty of oil in the 
pan, then turmeric added for the basic curry, generally a shrimp 
paste product, and any additional spices, optional coconut milk or 
tomatoes, maybe chopped cilantro root, added, and all cooked until 
thick enough to break apart and release the oil -- you then add your 
meat, fish, or vegetables. This basic method is used for a huge 
variety of curries, my favorites being the tomato-ey shrimp or fish 
version, a beef version with coconut milk instead of tomatoes, and 
their version of beef vindaloo, which is killer hot, a little 
vinegary, and with just a little tomato added to give an extra 
dimension to the flavor.

So, there I am caramelizing twelve pounds of onion/garlic/ginger 
puree, and as I say, when I make a pint of this stuff I'm used to the 
various sulphur compounds in the onion reacting with either the 
ginger and/or the iron pan to produce a slight bluish-green color 
which goes away as the product cooks (it turns grey, then brown, then 
sorta reddish). I left the kitchen for a few minutes with my pans on 
low heat, and came back to find an astonishingly bright aquamarine 
blue-green stuff in the pans.

I haven't seen any evidence to suggest this is either unnatural or 
dangerous (if I'd been using an unlined copper or aluminum pan, I'd 
be worried), but man, this was bright for a food product not 
deliberately colored that way.

Will advise if there's an explosion or anything...

Adamantius


-- 






"S'ils n'ont pas de pain, vous fait-on dire, qu'ils  mangent de la 
brioche!" / "If they have no bread, you have to say, let them eat 
brioche."
	-- attributed to an unnamed noblewoman by Jean-Jacques 
Rousseau, "Confessions", pub 1782

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