Why do aluminum pans turn color

[jjdbike]

Hello folks,

We do casual entertaining a good deal, bbq’s, potlucks, etc.. I use disposable aluminum pans a lot. I generally reuse them as long as they’re still usable. When I put them in the dish washer they turn dark colored, like they’re tarnished.
Does anyone know why this happens? Is there any way to prevent it from happening, other than not putting them in the dishwasher? Are they still safe to use?
Thanks in advance!
JD

[Ace]

Hello folks,

We do casual entertaining a good deal, bbq’s, potlucks, etc.. I use disposable aluminum pans a lot. I generally reuse them as long as they’re still usable. When I put them in the dish washer they turn dark colored, like they’re tarnished.
Does anyone know why this happens? Is there any way to prevent it from happening, other than not putting them in the dishwasher? Are they still safe to use?
Thanks in advance!
JD

AI response from a Google search:
Aluminum pans turn color due to oxidation (forming a harmless gray/black oxide layer from air/heat), chemical reactions with acidic or alkaline foods (like tomatoes, vinegar), dishwasher detergents (harsh chemicals causing dark stains), or burnt food/oil residues, all of which create discoloration from a protective oxide layer to dark spots or white mineral buildup, but the pan is generally still safe to use.

[Uncle Bob]

Typical dishwasher detergents are highly alkaline. People who put their aluminum bodied meat grinder attachments in the d/w find that out too.

[CaptainMike]

Ask me how I know...

[yakima]

On the other hand, you may have lucked into mistakenly produced solid silver pans, which easily tarnish!

[Ace]

^ I want some of those... :-)

[yakima]

My wife's brother is a 3rd generation jeweler. We gotta rule. Never put gold or silver in the dishwasher.

[Michael_in_TX]

Yall making this turn-darker thing up. I've been putting my cast iron pan for years in the dishwasher and they come out with this lovely, perhaps even gorgeous, iron-red hue.

[LA Pork Butt]

Funny 😂

[Uncle Bob]

And then you do a one star review on Amazon?

[texastweeter]

Somebody get a rope...

[Hulagn1971]

Yall making this turn-darker thing up. I've been putting my cast iron pan for years in the dishwasher and they come out with this lovely, perhaps even gorgeous, iron-red hue.

🤣🫠🫠🫠

[RolfTaylor]

The old dishwasher detergents didn't have this problem. It began happening when they (finally) eliminated the phosphates from dishwasher detergent.

I don't know if there are comparisons somewhere, but it is possible some brands do this less than others.

[texastweeter]

We have a septic, bring back phosphates please, my grass will be greener.

[briano52]

My aluminum sheet pans and trays all darkened and took a grainy finish from the dishwasher. I know it is only cosmetic, but I didn't like it. Switched to stainless steel and those pans come out of the dishwasher shiny and bright. I still don't put any knives or cookware in the dishwasher but the sheet pans and trays don't seem to mind.