What turns aluminum cookware black?

Weekend Warrior

I have a very old 8 qt. aluminum pressure cooker that has turned black from the steam under the pressure hickamajigger thingy. I also have a full Kinetico water system with softener, etc. Is something in the water turning it black? The salts? The weird thing is, is that whatever "it" is, is not turning the inside black. :blink: I also only hand-wash this piece, so not dishwasher related..... I use it mostly for making very tough pieces of meat(country ribs, etc.) tender quickly so not much acid involved either.

Weekend Warrior

Thanks for the link Tweev. I actually did some g**gling myself before I bothered the forum, but couldn't find anything. Country ribs are dirt cheap and mighty fine eating if you let the pressure cooker do the work instead of time. I toss in some fresh herbs and make gravy with the leftover drippings. Pretty good stuff over stove top stuffing and mashed taters. :laugh: I don't have time to do low and slows after work, so the pressure cooker comes in handy.

fishlessman

wonder what effect the chlorine would have when heated, it completely ruins stainless. is it city water. my pots turn more grey than black over time but the pressure cooker gets hotter

Weekend Warrior

hey fish. It's city water, but it's crappy. Lot's of dissolved solids/hard, but like I said, it runs through our $$$ Kinetico system before we use it. I dunno. The reverse osmosis is supposed to remove the chlorine I think.

fishlessman

check out what city water can do. this is a stainless pipe, less than a year old. im not sure if its cracking from the steam side or the exterior where some water was dripping on it. was shiney new a year ago. pretty sure it was the chlorine that cracked it up, its almost brittle now