Aluminum and Other Metals in the Dishwasher

[Chris Amirault]

I worked in a couple of restaurant kitchens as a young adult, and no one ever kept the aluminum stuff out of the dishwasher. I never used to hold my own aluminum popcorn pot out of the dishwasher until I read, somewhere, that Calphalon recommended keeping their anodized stuff out. Now I'm vexed. Fat Guy tells me that he ignores the recommendations and has been putting his aluminum stuff into the dishwasher every day for years. I'm particularly interested because the KitchenAid grinder components have aluminum on them and need, for obvious reasons, very sanitary cleaning.

So what's the scoop? What exactly happens to aluminum in the dishwasher? What do you do?

[tim]

Chris,

I think that the alkalinity of dishwasher detergent damages/removes the anodized surface of aluminum cookware.

Natural aluminum may become stained for the same reason. In my experience, a dishwasher with an effective rinse cycle will not damage natural aluminum.

Tim

[Chris Amirault]

Are the effects merely visual?

[Fat Guy]

I'm particularly interested because the KitchenAid grinder components have aluminum on them and need, for obvious reasons, very sanitary cleaning.

←

I had a friend over awhile back and we made hamburgers. He brought over his KitchenAid grinder attachment and we connected it to my KitchenAid mixer. Afterwards, we put the thing in the dishwasher. He doesn't have a dishwasher. He said it was the cleanest he had ever seen it since the day it came new in the box. I don't think there was any damage to the product.

I don't buy an aluminum pot assuming I'm going to own it forever -- cast-iron or copper, yes, but everything else is disposable. If I can get ten years out of it, I'm happy. I do believe that the dishwasher will shorten the usable life and diminish the appearance of anodized aluminum. A couple of the anodized aluminum pots we got when we got engaged in 1993 are now nearing retirement. I'm sure without the dishwasher they'd have been good for another decade. But I don't care. It's just not worth washing them by hand.

[JAZ]

I find the effects partly visual and partly tactile. Sometimes aluminum tools that have been through the dishwasher get a kind of weird feel to them, as well as spotting and turning an unattractive shade of gray. But I'm not sure what the process at work is, because not all aluminum does that. My Chicago Metallic sheet pans, which are "aluminized steel," are fine in the dishwasher. My garlic press, on the other hand, has passed the point where it even looks like aluminum (I like to think it has a patina). I use it anyway.

I don't have any anodized cookware, though, so I'm not sure how that does in the dishwasher.

[slkinsey]

With aluminum you'll eventually get some pitting from the dishwasher. This is largely cosmetic, but will also make the cooking surface more sticky.

[Chris Amirault]

So what reacts with what? We're thinking about switching to more environmentally-friendly cleaning products; is it likely that doing so will eliminate this problem? What is the ingredient in dish detergent that doesn't like aluminum (or vice versa)?

[budrichard]

Aluminum will dissolve in an acid as well as be attacked by a base. I assume that the dishwashing preps are basic in nature. I had some Campagnolo chainrings in my garage against the concrete(base), the chainrings powdered over the years of not using them. An expensive lesson.-Dick

[Andrew T]

Here is a video on aluminum after dish washer. The aluminum cookie sheet is somewhat blacken.

 

The video also shows how to remove the blacken color using oven, cream of tartar, and disposable turkey pan (no scrubbing).

 

 

 

[Thanks for the Crepes]

I used to throw everything in the dishwasher including my high carbon steel kitchen knives  and aluminum cookware when I was young and inexperienced. That was a big mistake and I learned from my errors.

 

Bare aluminum will come out of the dishwasher coated with a white powdery substance that will come off on your hands sometimes. Cooking spaghetti sauce or anything else acidic will clean up aluminum but after reading about a possible link between Alzheimer lesions and aluminum I no longer cook anything acidic in aluminum. The reason the cream of tarter in the above post works is that it's acidic.

 

I have an old heavy (in thickness not weight) oversized aluminum roasting pan that is so covered with polymerized oil, though, that I can safely throw that in the dishwasher and still do. I have a lot of roughly 9x13" roasting/brownie pans, and this aluminum one is on the bottom of the nested stack, but I always dig it out for roasting chicken or prime rib or something. It's not pretty, but it sure is useful to me. So aluminum can be seasoned like cast iron, and at least when you only use it for roasting fatty meat like I do, won't suffer from a trip through the dishwasher.