Knife Knowledge/Knife basics: Patinas - Protective Rusting! Oxidation on carbon steel blades!

We take a look at the different oxidation that can occur on a carbon steel knife. If you are new to ownership, you should understand that this needs to happen. The knife comes in shiny and new. This is short-lived. Rust can be damaging. We can force a protective layer of oxidation or we can let it happen naturally. To on the sharpest blades we must deal with this situation. We explore the different types of Patinas. We explore the opportunity and option to remove it or how to live with it.

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The knives featured are

Hitohira Tanaka Kyuzo Blue #1 Migaki Kiritsuke Gyuto 240mm -

Hitohira - Tanaka x Yohei - Blue #1 Kasumi - 270mm Gyuto - Cherry Handle -

YU KUROSAKI A2 YANAGIBA 300MM

Masamoto KS Series White Steel No.2 Wa Gyuto 240mm -

Kuku 180mm AS Gyuto

[grebecknives]

Thanks for sharing your knives and sharing what you've learned about high carbon steel. Not many people understand all our grandparents (or maybe great-grandparents) knives were high carbon steel and you can tell the use and care that was taken to keep them 'ready for use' in the kitchen. They were all covered with a patina over time.

[trappenweisseguy]

I saw pictures of a forced patina put on a knife once using mustard with bubble wrap wrapped around it. There was a cool pattern of rings left somewhat like engine turning. My Tojiro still has its kuroichi finish intact after several years and it has proven remarkably non reactive. Never seen a 240 nakiri before either.

[bidin]

I remember seeing a video of tanaka San said that he make tools not a work of art and tools are made to being use...keep up the good work greg

[andrebarroso]

This nakiri is unbelievable. Beautiful knives

[davidsaid-dgym]

great stuff! thanks for sharing your honest thoughts

[andrebaran]

The first time I saw a knife change colors I was just amazed. I love that amazing blue patina that comes through after I chop a pile of onions. I do wipe off my knives pretty well afterwards and oil all of them regardless of how long they sit on the shelf.

[adrianhh]

Kato as just came in and this video is up. Awesomeee!!!!

[tom_nuyts]

very good demonstration and competent informations . I use the sam trick for the anti-oxidation of my "Solingen Windmühlenmesser - with very thin grinder blades of carbon steel". And more and more I try to avoid oxidation and patina effects, because actually they decarbonize the surface and make it more and more uneven, so that the cutting experience suffers from this increasing roughness. (Those guys in Solingen originally developed a special blue fine polishing of their HRC 61 blades to avoid rust development in times before stainless steels came up ... rather effective, I have to say...) @ rust eraser: instead of that "unknown" material and composition I use a leather belt to clean up the dry blade, very successfully and very carefully

[erickzhou]

Wowww I was just searching for patina information today

[billlbilsontonling]

Great vid very informative, you can also use mineral oil for the blades to prevent them from rusting. My Tanaka Yohei recently got some rust from humidity and a barkeepers friend slurry with water does a great does a great job of removing the rust without changing the finish
Edit: also metal polish works wonderfully for removing rust

[waynethebarber]

Thank you for a nother great video. I always learn so much. I just ordered, and receiving soon 2 high carbon steel knifes. The Mitsumoto Gyuto and Kiritsuke knifes. These are more of there low end knifes And I am looking forward to the patina. I have one question about the knife blade, because of the high carbon will it give off a taste on the food I cut. This is a very big thing for me. I went with a less expensive knife because these are my first Japanese knifes. I know I have a lot to learn. I am looking forward to watching the patina grow. Again, thanks for all the work you put in your videos....

[sonkekoster]

I have a KS-Style Burrfection Launch Edition blue #2 240mm gyuto with stainless cladding. The core steel is highly reactive. So I let the patina form and stay at the core steel. But as you said - this work great for stainless clad knifes and in my opionion looks great for many knifes of that kind. But for blades with complete reactive surface, I would clean them on a regular base for aesthetic reasons. I takes only a few minutes to do so and make fun. You have time to look at the knife.

[Reza-nzre]

For the Mirror Finish blade you can try Koyosya/ Koyo Blue polishing compound Gregg. Maybe it might help bring back the mirror finish shine. That's what chef use on their knife everyday to clean our high carbon mirror finish Yanagiba.

My 13 years old Aoniko Yanagiba is clean without any stain in it because I clean them everyday and take care the knife. Believe me, it will look beautiful like new if we take care of it.

Mirror Finish Yanagiba always work the best for the ultimate clean cut. Damascus is good looking but for smooth cutting feel I prefer mirror finish. Also I see almost all head sushi chef use mirror finish Yanagiba (Ni-Mai) or Mirror Finish Honyaki.

[TheAmazingchickens]

I have a Gyuto in Sk-5 steel, which is just a straight downgrade from blue or white steels, still a lot harder and easier to sharpen than any stainless, but with more impurities (IE sulphur) than those premium blade steels.
One of the perceived disadvantages of this is high reactivity, but I actually love the patinas that form on the blade.
I use the knife all the time at work and it has forms a very complex mottled patina that changes all the time, made of strong Grays and blacks as well as faint blues, It gives the impression of an abstract or impressionist painting, I think it's unique and I wouldn't change it for the world.

[aexeferino]

Informative video! I could never own japanese knives as they seem to be a lot of work but I admire your dedication to these. They are very very very beautiful

[sonkekoster]

Hi Greg, have you ever thought about to bye a Masamoto KS in the swedish stainless steel variant? It's identical in shape and grind only the steel is different probably Scnavik 19c27 vs. white #2. So it's a little bit softer steel - HRC +/- 60. But it will stay shiny. Maybe you add one to your collection?!

[sonkekoster]

One last suggestion. For your Hitohira Tanaka 270 gyuto with the kasumi finish. I read on the chef knife to go page the Konosuke Fujiyama Kaiju made by Tanaka come with special finger stones to 'maintain and enjoy the finish'! These knifes have the same finish. Maybe you can get a hand on such a finger stone for your Hitohira knifes? But I have no idea how expensive they are.

[sonkekoster]

Hi Greg, I have made my own experiences with patinas. In general I like carbon core knives with stainless cladding. The patina on the core looks great in every aspect. For full carbon blades with iron cladding, it depends very much on the finish. I have currently only one japanese gyuto with carbon core and full iron cladding. This is one of my heirlooms - my 210 white #1 damascus (house forged) gyuto from Yoshikazu Tanaka. This knife builds a beautiful patina. And what I really like, is the different contrasts of colors due to the damascus cladding. So I really like the look. The same would be true for a knife with a iron Kurouchi finish or a Kasumi finished knife like your Hitohira for Yoshikazu Tanaka. By the way, a beautiful knife! On a Migaki, Mirror finished or mono steel (KS) knife, I am not so sure if I would like the look. I think, I would use such a knife only to cut proteins - for example a Yanagiba and keep it shiny.

[davidhamtaro]

Thanks for the informative video. I’m a knife newbie and was using a Morakniv carbon knife to chop up some fruits and it turned blue. I was in shocked and about to contact Mora if the knife is defected.

[mikepalma]

Love your videos and your collection! I have been trying to find a 270mm or 240mm Hitohira Tanaka x yohei kasumi blue #1 and its like a unicorn lol. No one has one.