Why reoil a cast-iron pan after usage?

I've been recommended to reoil my cast-iron pan by letting it absorb some oil on the remaining heat of the stove before drying it, each time after using it.

Is it important to do so, and what difference does it make? There should still be a lot of fat left from simply rinsing and drying the pan.

Best Answer

AFAIK you need to heat the pan to let the oil oxidize and polymerize¹ so that it will form a chemically protective and non-sticking coating.

If you wash your cookware with soap you will have to do it every time. For that reason some people don't wash cast iron at all and wipe it with a clean cloth or paper towel after using. (Burned oil is apparently not very tasty to bacteria and fungi so your pan stays relatively clean and bug-free.)

From my personal experience, meat sticks to untreated cast iron like glue, but on a well-maintained thick iron pan it glides like on Teflon.

¹ I don't know if it makes any chemical sense because all references to polymerized fats I could google up were in relation to reoiling (seasoning).

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Does cast iron need to be oiled after every use?

\u2014 To get the best out of your cast iron skillet, it's recommended that you oil it after each use. However, depending on how frequently you use it, 2-3 times a year is sufficient. How can I tell when my skillet is seasoned properly? \u2014 A well-seasoned skillet will be noticeably dark with a shiny, semi-gloss finish.

Do you have to season a cast iron skillet after every use?

Every time you use your cast-iron skillet, you're wearing some of the seasoning down, and eventually it won't function as well. So season it again whenever you see dull spots. Or do what I do: season it whenever it's out and your oven is on.

Do I need to clean cast iron after use?

Get right to it: Clean the skillet immediately after use, while it is still hot or warm. Don't soak the pan or leave it in the sink because it may rust. Add hot water: Wash the skillet by hand using hot water and a sponge or stiff brush. (Use tongs or wear gloves if the water is extra hot!)

When should I Reseason cast iron?

Clean after every use: While skillet is still warm, wipe it clean with paper towels to remove excess food and oil. ...

Lightly reseason after each cleaning: Dry thoroughly (do not drip-dry) and set over medium-low heat until all traces of moisture disappear.

how to clean a CAST IRON PAN after cooking

More answers regarding why reoil a cast-iron pan after usage?

Answer 2

Typically I (occasionally rinse and then) heat the pan and grease with shortening when the seasoning looks like it could use a touch up. When dirty, I heat with a bit of oil and clean out with salt; this reduces the viscosity of the oil making it likelier to fill in the porous surface of the skillet. Since it appears you are asking specifically why the fat/oil needs to be heated, I will address that. However, there is already wealth of information on cast-iron seasoning in these two earlier posts.

The purpose of the heat is three-fold;

if you previously rinsed it will help evaporate the water
by heating the surface you make the grease (or oil if you like) apply more evenly and thoroughly due to the lowered viscosity allowing the oil to penetrate deeper into smaller pores/pits of the iron
if you haven't used the pan in a while the seasoning (because it is composed of fats and oil) may go rancid and the heating can prevent that.

Answer 3

Iron rusts. A protective coating of oil helps to prevent the rusting. I've found that my cast iron pans rust less and need less protection as they acquire the sort of patina that Mischa describes.

Answer 4

Yes you should season the pan after each use. I've used the Flaxseed oil principle. It does work, but it makes the pans smell strange and the food tastes a bit weird. This is because it is food grade linseed oil. This kind of oil is used for oil paintings.

The best thing is to use either vegetable shortening or lard. You can heat the pan on low heat. Use a cotton cloth to spread the vegetable shortening inside the pan, then crank up the heat to 7 or 8 until there's a bit of smoke. This is the carbon layer being burned onto the pan. Wipe the pan down again and place in the oven to cool.

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