http://ask.metafilter.com/tags/coppersulfate Questions tagged with 'coppersulfate' at Ask MetaFilter. Sat, 14 Jul 2007 02:08:06 -0800 Sat, 14 Jul 2007 02:08:06 -0800 en-us http://blogs.law.harvard.edu/tech/rss 60 http://ask.metafilter.com/66965/As%2Dan%2Dunmuddied%2Dlake%2DFred%2DAs%2Dclear%2Das%2Dan%2Dazure%2Dsky%2Dof%2Ddeepest%2Dsummer Why did my garlic turn blue? I was cooking salmon on the barbecue yesterday and when it was done I noticed the garlic had turned bright blue. I looked it up and it seems that garlic in pickling solutions will sometimes turn blue. There are various explanations of this, but the most common one is that in an acidic solution, sulfur containing compounds in the garlic react with even minute amounts of copper to form copper sulfate. This is what I had assumed had happened, because I remembered hydrated copper sulfate being exactly the same colour. <br> <br> There were a few other explanations of how the colour forms, but assuming that this explanation is correct, where did the copper come from? The other ingredients were soy sauce, rice vinegar, ginger, and slices of apple on a wild sockeye fillet. I cooked it in tinfoil.<br> <br> I apologize in advance for what is probably a trivial question. It's just been bothering me for a whole day now. tag:ask.metafilter.com,2007:site.66965 Sat, 14 Jul 2007 02:08:06 -0800 barbecue blue bluegarlic copper coppersulfate garlic salmon sulfate [expletive deleted]