Carbon Steel
Patina is part of the journey.
Carbon steel is one of the reasons Japanese knives can achieve exceptional sharpness and cutting performance.
It also asks for something in return:
A little more attention.
What is patina?
Over time, carbon steel naturally changes colour.
You may see shades of:
Silver → Straw → Gold → Grey → Blue → Charcoal
This is called patina.
It's a natural surface oxidation that develops through use and contact with food, moisture and air.
Patina is normal.
It is part of the character of a carbon-steel knife. ProTooling and Chef’s Edge both describe patina as a normal part of carbon-steel use.
Patina isn't rust
This distinction matters.
PATINA
A relatively stable colour change that develops naturally over time.
RUST
Active corrosion that can appear as orange, red or brown spots and should be addressed.
The best way to prevent rust is simple:
Keep the blade clean and dry.
During cooking
You don't need to obsessively wipe your knife after every single cut.
But be particularly mindful of acidic ingredients such as:
- Citrus
- Tomatoes
- Vinegar
- Pickles
- Some fruits
If you're working with acidic ingredients for an extended period, wipe the blade periodically and dry it afterwards.
ProTooling specifically recommends being mindful of acidic ingredients rather than treating constant wiping after every ingredient as necessary.
After use
Wash.
Use warm water and mild detergent.
Dry.
Immediately and thoroughly.
Store.
Somewhere dry and protected.
That's it.
Long-term storage
If you're storing a carbon-steel knife for more than a few days:
Clean → Dry → Oil → Store
Use a very light coat of appropriate food-safe knife oil.
Remove the oil and wash the knife before returning it to service.
What if rust appears?
Don't panic.
Early surface rust can often be removed without permanently damaging the knife.
The important thing is to deal with it early and avoid aggressive methods that unnecessarily remove steel or damage the finish.
If you're unsure:
Send us a photograph.
We'll help you determine what you're looking at.
The beauty of carbon steel
A stainless knife tries to stay the same.
A carbon-steel knife tells the story of its use.
Every mark, colour change and patina is part of the knife's journey.
It becomes yours.
Don't fear the patina.
Understand it.
Care for the steel.
And let your knife develop its own character.