Foods/Ingredients That Stain Knives Fast

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mhlee

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I happen to prefer carbon steel knives. But, as with all carbon steel knives, they require some additional care when it comes to cutting certain foods, such as onions, acidic fruits, etc.

I'm generally very diligent about wiping my knives as soon as I use them; I almost always wipe them down immediately after use and/or wash them off immediately after use.

Yesterday, I was cutting a certain vegetable, wiped off my knives and washed them immediately after use. However, I neglected to completely wipe down my board. I left my knife on the board, and within minutes, I had stains on my knife.

The culprit: water spinach aka Ong Choy.

In your experience, what items stain carbon steel knives the fastest?
 
I don't know if it is the fastest but strawberry gives a very nice and dark patina :D
 
I don't know if it is the fastest but strawberry gives a very nice and dark patina :D

I can't think of anything that competes with strawberries, at the moment. Definitely a quick way to get a good black patina.
 
On white #2 or O1 - in this order; onions, Strawberry, my blood (although this last one turns into a very nice patina if used on higher polished finished blade :biggrin:)
 
My Yoshikane kasumi (SKD12 (okay, it's often classed as "semi-stainless") core, stainless clad) was pretty slow to develop a patina with the usual suspects (onion, pineapple, cooked chicken/beef etc.) although eventually it took a pleasing blue-ish patina. I few weeks ago I cut up an overripe avocado with it and got instant yellow patina over the existing one - assume this was from reaction with oleic acid/ other long-chain aliphatic acids.
 
I always find that radicchio reacts badly to carbon, both on the food and knife.
 
For me it seems to depend on the maker. Some white # 2 I have react instantly to certain things, others not.
 
Baby artichokes seem to make everything black. Including your fingers!
 
Bananas, avocados, mangoes & blood (esp hot).
 
any recommendations for a "gentle" way of removing these stains? oh yeah, red pepper
 
any recommendations for a "gentle" way of removing these stains?

Fine natural stone mud is the most effective, non scratching way to clean off patina I have found. I just use a cork to rub the mud on the blade.
 
Banana.

I just sliced one with a cck to go in my kid's porridge, left three discs on the blade for literally 15 seconds, and came back to jet black polka dots. Kinda neat.
 
worked like a charm (gently used synthetic stone mud though, bad call?), many thanks
 
So strawberries and onions will turn your knife black. Will the fruit and veg turn black(ish)?
 
My personal fave is cooked beef. The blue patina is amazing. I think that's what hooked me on carbon. I bought a carbon knife from Korin many years ago and the very first night I used it, I sliced a steak and literally watched the patina appear on the blade as I sliced it. Awesome...
 
My personal fave is cooked beef. The blue patina is amazing. I think that's what hooked me on carbon. I bought a carbon knife from Korin many years ago and the very first night I used it, I sliced a steak and literally watched the patina appear on the blade as I sliced it. Awesome...

I just had this very experience and reaction! One day old Gesshin Ginga gyuto. I showed my wife who was... a bit... less excited.
 
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