[ars]

> Heat the pan after cleaning, evaporating all water.

Don't do that. It causes rust.

Metal rusts MUCH faster when hot than when cold. If you have wet metal that you are worried will rust get it as cold as possible, and let it dry. Best place is in the fridge - it's cold, plus low humidity helps.

A fridge is not necessary for cast iron, but don't heat it when wet.

[learc83]

How is heating it up for 2 minutes to dry it off going to cause rust compared to the 20 minutes you spent cooking with liquid in the pan?

[ars]

Much more oxygen as it dries. You are not supposed to boil water with cast iron, you need oil when cooking which protects it from air.

The point is don't warm it to dry thinking it will rust less since it's wet for less time. Just let it dry in regular air.

[learc83]

I suppose that might be true, but have you actually done the math here?

If it dries say 50 times faster, does iron rust more than 50 times faster at 400F than at 70?

I have no way of knowing either way, but I've got a cast iron pan that belonged to my great grandmother and I remember my grandmother heating it to dry it off. My mom did the same with it, and now I've done the same--no rust.

[ars]

I didn't do math. I did an experiment.

I took two identical pieces of metal. Dried one in a warm stove the other on a table.

The one on a table had no visible rust. The one in a stove was completely orange.

[learc83]

I don't doubt that warm metal rusts faster, just how much faster.

There's a pretty big difference between drying something in a warm stove vs applying a direct flame to it on the stove top.

It takes just a few minutes to get the skillet hot enough where the water pretty much instantly evaporates. I'd imagine putting it in a warm stove took much longer to completely dry it.

[ars]

Direct flame would be even worse. It will rust much faster than it will evaporate.

Reaction speed doubles for every 10 degrees F, but evaporation doesn't.

[andrewflnr]

In my house, we stove-dry pans constantly, precisely to prevent rust, and we never get any. It's not intentionally an "experiment", but it's enough to make me think there's an issue with your methodology.

[ars]

You probably would not get rust anyway, so stove drying isn't hurting anything much.

But it's certainly not helping.

The methodology was not complicated: I washed some porous/rough metal under the faucet, dried it with a paper towel, then put one piece in the oven at 170F, one on the table.

[webnrrd2k]

Maybe iron will rust faster when hot, but I don't think heating it to dry it is an issue -- I do that fairly often, and haven't had a problem.

Here's a counter example: There are many tons of metal in hot desert climates that have a small amount of rust on them, but nothing like the kind of rust from a cold wet climate. There may be complications from cooking, but, and this is without giving it much thought, I'd say that water is a much larger factor than heat.

[ars]

> in hot desert climates

You still need water.