Blade finish and food release-suggestions?

[GeneH]

How does the sanded finish on a gyuto affect food release and general performance? (Tagging off the thread where someone else was asking about mirror polish and there’s suggestions the finish has more stiction.)

I’ve three knives, 2 stainless and one carbon, that I’m on the tail end of refurbishing. All have been smoothed on a Gesshin 1K, and started on the 6k, but I think I want to just surface finish with a quick pass using fine belts on my 2x42.

I can always start with a mirror-ish and go down from there I suppose. Does the direction of the scratch pattern make a difference?

 

[Boynutman]

Bumping this topic, I am also curious about insights. I have an almost mirror polish gyuto that suffers from food sticking to it. Considering to make it less polished (spine to edge scratches) - or should I do the reverse and ‘super polish’ it?

Thanks!

 

[M1k3]

The more polish, the more sticking. Especially wet stuff, like cucumbers. Somewhere around 400-1000 sandpaper, 1k-4kish stones seems the best compromise with the bonus of hiding scratches from use easier. In my opinion.

 

[NameAlreadyTaken]

What about a coffee etch as per: Damascus Thoughts: Thinning Impact
Would that improve food release? Or is this just an aesthetic thing, and the food release is just down to the roughness / smoothness of the blade surface prior to any aesthetic etching?

 

[M1k3]

Not really sure if it would help. If you do it, it needs to be smoothed before use. It'll cause lots of drag without some buffing/smoothing out.

 

[lemeneid]

There was a bead blasted finish Mazaki and Wat just recently on BST. I'm pretty sure those are very food sticking resistant. But at the same time, these kinds of blades will create lots of drag or friction on the blade face, reducing its cutting performance too.

 

[NameAlreadyTaken]

Not really sure if it would help. If you do it, it needs to be smoothed before use. It'll cause lots of drag without some buffing/smoothing out.

Good to know. Thanks for sharing your experience M1k3!

 

[danemonji]

The grind type and cross section profile influence more the food release of the knife while the blade road finish has minimal effect. If the grind is flat grind then food release will be minimal. Convexity in the grind will help improve the food release. Smoothing the blade road finish will just help reduce the friction of the cut. Other than that having a kasumi finish with contrast is an estetic factor.
For the best food release I use Kurouchi knives with good geometry.

 

[Boynutman]

Thanks for all your feedback. The knife is a 240mm Hattori HD (I think an OEM knife, appears to have been sold under different names).
The grind is nice, good convexity (definitely no wedge), thin behind the edge, so no suspicions there. Cuts fine in non sticking food. Stainless damascus finish. Hadn’t even considered etching.
More polish = more sticking is also what I figured. But some stuff works counter intuitive so I appreciate all your thoughts !
I will get myself some 500 and 1000 grid sandpaper and see what happens.

 

[Carl Kotte]

Thanks for all your feedback. The knife is a 240mm Hattori HD (I think an OEM knife, appears to have been sold under different names).
The grind is nice, good convexity (definitely no wedge), thin behind the edge, so no suspicions there. Cuts fine in non sticking food. Stainless damascus finish. Hadn’t even considered etching.
More polish = more sticking is also what I figured. But some stuff works counter intuitive so I appreciate all your thoughts !
I will get myself some 500 and 1000 grid sandpaper and see what happens.

The damascus may not look the same afterwards, but if you’re ok with that sanding sounds like the right way to go.

 

[Boynutman]

So... reporting back. I sanded the blade, spine to edge direction strokes only (no reverse, to avoid fish hooks). Started with 320, then smoothened it with 500 then some brief smoothening with 1000 grit. The mirror is gone, with my fingernail I can just feel the scratches, but it feels very smooth. Didn’t dare to take it further, for now.
Before and after pics below.

Does it improve food release? I think it does, somewhat.
I think it reduces drag too.
Not a different knife, but subtly improved.

Most of all I am really happy with the new look, always thought the mirror damascus looked like cheap chrome plating. The new look is more serious, with a very subdued damascus left.

Recommended!

 

[Nemo]

The grind type and cross section profile influence more the food release of the knife while the blade road finish has minimal effect. If the grind is flat grind then food release will be minimal. Convexity in the grind will help improve the food release. Smoothing the blade road finish will just help reduce the friction of the cut. Other than that having a kasumi finish with contrast is an estetic factor.
For the best food release I use Kurouchi knives with good geometry.

It is certainly true that the geometry is king in food release. However the blade finish can certainly have an impact and I think it shouldn't be overlooked.

 

[dafox]

The Cleancut Kashima Sanjo is a knife with a finish that is very non stick. Geometry wise it is pretty laserish but still manages to be pretty non stick due to the bead blasted like finish that feels like that rough kind of non stick cookware type of finish.

 

[Boynutman]

One mystery left: what would aid food release more: length wise/kasumi scratches, or spine to edge scratches?

 

[spaceconvoy]

I can't imagine the direction of the scratches would make any difference. Maybe a laboratory somewhere could perceive it with an electron microscope. But there could be some unintended consequences... Given that a more pronounced bevel has better food release, refinishing a knife with spine to edge scratches would smooth the transition between bevel and blade face, and might worsen food release slightly.

 

[M1k3]

I like them parallel with the edge, handle to tip. Giggity. Not for food release reasons, for hiding scratches. They seem to happen in that direction more.

 

[ian]

I like them parallel with the edge, handle to tip. Giggity. Not for food release reasons, for hiding scratches. They seem to happen in that direction more.

and it’s also easier to refinish. Spine to edge sanding is a pain.

 

[ian]

The Cleancut Kashima Sanjo is a knife with a finish that is very non stick. Geometry wise it is pretty laserish but still manages to be pretty non stick due to the bead blasted like finish that feels like that rough kind of non stick cookware type of finish.

Hmm, that knife did have good release for a near laser. I wasn’t sure how much of it was geometry and how much was finish though. Many other Yoshis are pretty thin with good release. I typically hate that kind of finish because it’s impossible to reproduce, and sometimes (eg with my Tanaka) it seems super grabby when going through food. Didn’t notice any grabbiness when I tried the Kashima tho. Maybe it did make a real difference, what do I know.

 

[M1k3]

I'm going to say that Kashima was geometry mainly. It is Yoshikane...

 

[Boynutman]

Now I am frustrated. Guys, next time, it is totally OK to lie to me!

Actually, good arguments. Thanks for all your input. Could have asked before. My Itinomonn has a lengthwise pattern. Didn’t even consider it until I got fed up with the spine to edge sanding.