Reseasoning cast iron: remove the old seasoning first?

In My Humble Opinion
21

220, is that Celsius? I’ve seen instructions to season cast iron anywhere from 200°F for 20 minutes to 500°F for 90 minutes. I put mine in the oven’s self-clean cycle last night, and it got rid of all the chipped ugly seasoning layers. This morning, I put a thin layer of Crisco on them and seasoned them at 450°F for an hour, and repeated that twice before cooking some bacon in one of the pans.

They are all three significantly better than they were, but there is a bit of dappling in the seasoning, probably because I put too much crisco on and it beaded up a bit. But they aren’t sticky, so I didn’t lay it on that thick. I’ll remember to go easier on the crisco next time (or I might try the flaxseed oil from the link above).

Anyway, I recommend stripping the old seasoning off if it is particularly ugly and chipped before putting another layer of seasoning on. But for most people with cast iron pans that aren’t that bad off, it shouldn’t be necessary. But then again, if you maintain them and use them frequently, you probably shouldn’t even need to reseason them at all.

22

I recondition cast iron by putting it in a wood fire and just turning everything to ash. When I re season I simply wipe it down with a thin layer of oil and cook it on the stove until it quits smoking, I do this about 3 times and make sure the fan is going.

23

Flaxseed oil will work much better than Crisco for seasoning a pan. Another name for it is linseed oil, which you probably know as a wood finish. This oil readily polymerizes when exposed to oxygen, something that Crisco doesn’t do.

24

I read that on the link above, but I’m not 100% convinced. I know how it polymerizes to finish both wood and paintings, but my understanding of how seasoning works is making me question that explanation.

Why does it matter what kind of oil you use, when the point is to lay down a microscopic layer of carbon that bonds to the metal? I thought any fat + heat would do the trick, but I’m happy to be educated further on the subject.