How rust prone is Shirogami?

[Noctis3880]

I suppose I shouldn't care too much since the knife in consideration is a relatively cheap $50 Tojiro kitchen knife, but I do remember that one unknown steel in a coworker's machete that turned brown before my eyes simply from being in contact with water.

I can do alright with 1095 so long as the metal has a smooth finish, but I'm kind of curious to know if Shirogami is more rust prone than that. The same seems to apply to CPM-M4 and 5160. The factory edge always rusts, but a quick resharpening fixes that up nicely.

 

[somber]

It's a carbon steel, so it's more prone to rust than a stainless steel, but you should have no problems taking care of it if you wipe your blade down after each use and maybe lightly coat it with oil occasionally. You can wipe it down olive oil, canola oil, or liquid parafin, even.

 

[C-9]

Oils are messy and generally unneeded for short durations of time. Not to mention cooking oils can become rancid.

 

[Noddy]

Don't know if this helps, but I used a friends not too expensive carbon steel gyuto recently for a few days. It rusted if I winked at it.

Way worse than 1095. My only thought is that it could have been made of blue steel or white steel - or at least something like O1 - which I find rusts appallingly.

If I dried it before putting it down it was OK, but it had to be really dry

 

[looker]

I’ve had no rust issues with white or blue carbons. I wipe down my knives (regardless of steel) occasionally while in use and will spend a few extra moments to make sure the carbons are dry before putting them away. FWIW, I find lower grade carbon steels, carbon steel cladding and bead blasted stainless way more rust prone.

 

[Noctis3880]

I've got camellia oil, but I've heard that evaporates pretty quickly, plus I normally don't oil knives I use even if it's once in a while. I do have some Mother's Mag and Aluminum Polish, which shined up my SR-1 blade real good. I figure I can polish up the blade if it becomes an issue.

Though I'm a bit curious about the formation of a patina on such a steel. I'm thinking if it rusts easier than 1095, it would probably only take a couple cuts into some limes to force the patina.

 

[somber]

For rust issues you can also cut a potato in half and use a cleaner like comet, scrub the knife with the potato and it should solve your problem. Do not heed C-9s advice - we store our knives with oil on them and have never had an issue.

 

[C-9]

I store my knives without oil and never have problems.

See a problem there? Unless you live in a high humidity environment, oiling simply isn't needed. Water is the culprit when it comes to rusting, and oiling does not remove water, it simply blocks water which is only useful if you knife gets wet for some reason after you've dried it. Oiling is still no substitute for drying though, and unlike other rustables where you can simply leave a layer of oil on them you need to remove the oil in order to use the knife.

You should never oil your knives unless you are planning on neglecting them for a long time, just in case, or if you have a specific problem with rust despite drying. It is simply an unneeded complication. you have to apply it, then when you use it you have to clean it up, and it is simply a fact that cooking oils do go rancid. Yes, there are oils that do not go rancid, like paraffin, but those are not cooking oils. If you do use knife knife frequently enough that each application of oil does not go rancid, then its also unlikely that the knife will rust simply because the knife is constantly being agitated, cleaned, dried, etc.

Do not heed Somber's advise. You simply can't tell whether or not you will need to oil your blades unless you try not doing it. And most of the time you don't. Try it without oil, make sure you dry well. If you still have rusting problems, then consider oiling your blades with NON-cooking oil, but foodsafe oil, like mineral oil.

 

[C-9]

To put it another way, if you don't already oil your carbon knives, there's no reason to do it. Oiling is only rust prevention for storage. It does not help at all when you're actually using it in the kitchen. If you want something that makes it more resistant to rust, building up a patina is a good idea.