Newbie on Maitenence
- Thread starter Silkheat
- Start date
This is what I have found so far:
Carbon steel is reactive. Good carbon steel darkens in reaction to acids and oxidizers in food. Rust of course is an oxidation process too, but in the first case you get FeO3, a "black rust" and in the second case you get FeO2, a "red rust."
Black rust is stable and durable. also, if oiled (cooking oil or grease from meats will do fine) black oxide "sets" and stabilizes the surface of the steel -- helping to prevent further rust.
A fine carbon steel knife will and rightly should develop a fine, blue/grey/black patina. You don't want to remove this surface. It's a desirable trait of a fine carbon steel blade.
Nonetheless, carbon steel blades discolor some foods -- eggs for example. I've never had a problem with fish, but I suppose fish might discolor from a reactive carbon blade.
Carbon steel is reactive. Good carbon steel darkens in reaction to acids and oxidizers in food. Rust of course is an oxidation process too, but in the first case you get FeO3, a "black rust" and in the second case you get FeO2, a "red rust."
Black rust is stable and durable. also, if oiled (cooking oil or grease from meats will do fine) black oxide "sets" and stabilizes the surface of the steel -- helping to prevent further rust.
A fine carbon steel knife will and rightly should develop a fine, blue/grey/black patina. You don't want to remove this surface. It's a desirable trait of a fine carbon steel blade.
Nonetheless, carbon steel blades discolor some foods -- eggs for example. I've never had a problem with fish, but I suppose fish might discolor from a reactive carbon blade.
Codger_64
Moderator
- Joined
- Oct 8, 2004
- Messages
- 62,151
You found quite a bit then, and there is a lot of truth in it. The darkening we call patina. It is natural and good. You can shine the knife to look like a new dime if you want to, but with use, it will darken again and in the meantime rust could be a problem.
Michael
Michael