Cast iron pan
The pan with the most confident folklore attached to it, and the manufacturer contradicts the most famous rule in it.
What not to do
Machine dishwashing is unsafe on Cast iron pan
Unsafe
Do not do this. The risk is established, and it is described below.
Evidence
Strongly supported
Sources
How to Clean seasoned cast iron
Lodge Cast Iron (Lodge Manufacturing Company) · Manufacturer documentation
Relied on for: That a dishwasher will remove the seasoning from cast iron and will likely cause rust. (states this directly)
Start here
What this is, what tends to go wrong with it, and what to do about it.
Made from
What tends to go wrong
Food heated until it carbonised and bonded to the surface. Time and softening do the work; scouring powder does the damage.
Why it is difficult: Contact time, Carbonisation, Adhesion and cohesion, Why old stains are harder
Hydrated iron oxide from corroding iron or steel. Distinguish a surface deposit, which cleans off, from active corrosion of the item itself, which does not.
Why it is difficult: Corrosion and passivation, Why old stains are harder, Adhesion and cohesion
Fats and oils, which water alone cannot lift. Removed by surfactants, by heat, by solvents, or by alkalis that convert the fat into soap.
Why it is difficult: Why oil resists water, Emulsification
The science behind this: Corrosion and passivation
In detail
A cast iron pan is bare iron carrying a seasoning layer — polymerised oil bonded to the metal by heat — which provides the release surface and the corrosion protection at once. Everything about its care follows from protecting that layer while accepting that it is renewable. The rule everybody has heard is that soap must never touch cast iron, and the manufacturer's own care guidance says otherwise: washing with a small amount of washing-up liquid is fine, and the manufacturer says the washing-up liquid sold today is no longer strong enough to remove seasoning. What the manufacturer does insist on is drying immediately and thoroughly, because the real enemy is water rather than detergent, and a light coat of oil afterwards. Two things do damage a seasoning: a long soak and the dishwasher. Rust on a cast iron pan is not the end of it — the layer is meant to be rebuilt, and scouring back to bare metal and re-seasoning is maintenance rather than repair.
What works
Steel wool is safe on, in specific conditions, Cast iron pan
Safe only in specific conditions
This is only appropriate within specific limits, and nothing is established outside them.
Only within these limits:
- For removing rust, not for everyday cleaning
- Dry the pan completely and oil it afterwards
- Heavier rust needs the pan re-seasoned in the oven
Precautions
- Check the manufacturer's instructions
Evidence
Supported
Sources
How to Clean seasoned cast iron
Lodge Cast Iron (Lodge Manufacturing Company) · Manufacturer documentation
Relied on for: That steel wool or a metal scrubber is acceptable for removing rust but not recommended for daily clean-up, and that larger amounts of rust require re-seasoning in the oven. (states this directly)
Related
- Cast iron pan is made from Seasoned cast iron
- Cast iron pan is commonly affected by Burnt-on food and carbon deposits
- Cast iron pan is commonly affected by Rust
- Cast iron pan is commonly affected by Grease
Sources for this page
Sources
How to Clean seasoned cast iron
Lodge Cast Iron (Lodge Manufacturing Company) · Manufacturer documentation
Relied on for: That the manufacturer permits washing with a small amount of washing-up liquid, and directs drying immediately and thoroughly and applying a light coat of oil afterwards. (states this directly)