Last night I cooked some broad beans in a cast iron pot with flour, butter, white wine and oregano. Throughout the process they gradually turned black, and they now look like they've been cooked in squid ink! I would really like to know what turned them black. I assume it's the cast iron pot, but what exactly is going on?
Thanks Andy. I didn't realise wine was acidic. (If I had I wouldn't have used it because we just bought the pot and were trying to keep acidic food off it for a while yet. I hope it hasn't taken too much of the seasoning off it.)