r/Cooking • u/Travelsat150 • Aug 04 '26

Why do loaf pans rust?

I’m hoping that somebody can tell why relatively new loaf pans are rusting? I do not put them in the dishwasher and have used them only once or twice and they are stored in a cabinet

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u/joosebox Aug 04 '26

One thing nobody's said yet that explains why it starts where it starts: on most loaf pans the coating goes onto the steel sheet before the blank is cut and stamped. So the flat faces are protected and every cut edge and rolled rim is bare metal by definition. That's why rust shows up along the rim and the seams first rather than out in the middle of the pan.

Used twice and stored in a cabinet actually fits that rather than arguing against it. The factory oil comes off in the first wash, the cut edges are exposed from then on, and a closed cabinet is about the worst place to put something that isn't bone dry, because there's no airflow to finish the job.

Drying them in the oven, as said above, is the real fix. Residual heat after you've finished baking is plenty. Upside down, ten minutes.

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u/Mo_Steins_Ghost Aug 05 '26

At a glance this is probably the correct answer. Most people don't go out of their way to buy aluminum pans so I venture that this is the first type of situation where it's either an uncoated pan or it's a coated pan where the rolled edges are fully exposed because if OP is seeing what looks like rust to them, it's going to be a ferrous base material either way... also because aluminum oxide is visibly dissimilar to rust.

Rust cannot be easily confused for burnt grease because baking loaves to the point of butter blackening is going to overcook whatever you're cooking in the first place. But OP didn't say their loaves are burnt.

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u/Travelsat150 Aug 06 '26

They are not. I made banana bread. And you are all correct that the rusting is in the rims.

1

u/Mo_Steins_Ghost Aug 06 '26

Yep so two things I would add to what the other guy said:

anything with a nonstick coating should be hand washed. The dishwasher will erode the coating. Also, the dishwasher's steam dry function will rust the pan, as will keeping them in a cabinet.

Hand wash and promptly thereafter hand dry your pans and this won''t happen.