Convex, Full Flat, or Flat Grind for the win? Let's put these Knife Grinds to the Food Release Test! 

That's amazing, thanks for catching that one! 👌🏽🙏🏾

My pleasure, thank you for watching!

That's amazing, thank you for the kind words. Much appreciated!

Thank you. Did you ever make a C-grind, S-Grind, or Walkschliff grind? They should do good too when it comes to food release. And is it true that knife makers call a convex grind the 'lazy grind', because it is apparently easy and fast to do on a slack beltgrinder?

I have done an s-grind before, but I typically stick with convex because I lean toward stone polishing more often than not. The way a lot of western makers make convex grinds is by leaving the edge thick on a full flat grind and then convexing that edge thickness down to zero or close to it with their grinders. Most of these guys are doing full flat from spine to edge and it gets almost infinitely more slower to maintain that constant full flat down to a zero edge thickness, so the round off the edge basically, by torqueing their wrists as they grind. Yes. That's super lazy. When I make convex grinds on say a honyaki, it will be more of a double bevel hamaguri grind, which is more methodically shaped from a shinogi or faux shinogi down to the edge. This typically takes stone work to further perfect and not look like junk. With wide bevels, it's nearly similar but a little more flat to make refinishing on bench stones easier, with a gentle convex going to the edge. I can't imagine doing a proper convex grind similar to what you see in high end honyaki as being easier or lazy.

Thanks for the kind words. I forgot to mention that a convex grind alone is not a guarantee for great food release. The thickness of the blade in combination with a convex grind is where the magic happens. A laser knife with convex grind would still suffer a lot of sticktion. So it's about the right thickness + convex, which sweetspot the JNS Kaeru clearly hits.

@@chefknivesenthusiast I 100% agree. Finding that perfect combination of convexity, thickness/thinness, and sharpness that doesn't tear or wedge and results in great food release is what makes a dream kitchen knife.

Handmade by a craftsman in Bali. 🙏🏾

Facts. But we're not talking about that one in this video.

@@chefknivesenthusiast 😮 you’re right i liked the picture so much in your video it’s exactly my favourite bevel-model. For me it’s convex when I have to choose the best one for food release in your video.

I'd love to throw in one of those! I think someone else mentioned this to me as well. Next time I'm dealing with this topic I want to see a Hollow grind, C-grind, S-Grind and Walkschliff grind in action. Plus one of the classic assymetrical Gyuto you mentioned. Great suggestion!

@@chefknivesenthusiast sounds like a perfect round 2!

Hi Kim, that makes two of us. I am really happy with the convex grind/thickness ratio on my Denka. I wouldn't thin it myself, unless it really needs it after many times of use and sharpening. The food release and stiction issue is a combination of the convex/clamshell grind and the sweet spot when it comes to thickness/thinness of a blade. A super thin laser type of knife with a convex grind (which in that case would be a marginal convex grind in the first place) woulds most likely still suffer from a lot of stiction. But indeed, making a super thin knife a little bit convex does make it a little bit less fragile. You can also put a micro bevel on the cutting edge to protect it. Have fun with your clamshell thinning project, hope it will give you the desired results!

The folks at @districtcutlery in DC thinned my 240 Denka BEAUTIFULLY. I enjoy sharpening, but I was GLAD to hire them on that one.

I must admit that I was not drawn to them at first glance. But after using the Gyuto and Nakiri a few times, my opinion has changed. They are very well made knives by Itsuo Doi and have a fantastic work horse grind. And when a knife performs, it instantly becomes sexy as well.

The black nashiji finish with the k tip looks wicked to me. This video was informative to me and I will be mindful of it when I eventually buy some steel and make some knives.

I think the difference in finishes on a blade will be marginal. I can imagine that a super smooth and highly mirror polished Yanagiba will slice through a raw piece of fish with the least resistance. I think different types of polishes are just for looks...but I might be wrong.

A Convex grind and the right thickness/thinness seems to be where the food release magic happens. So I completely agree with your 2nd paragraph. I'm not completely convinced about the effect of a Tsuchime finish (on itself) when it comes to food release, but I might do a video with a bunch of knives with a Tsuchime finish to see if there are Tsuchime blades that have great food release. I can imagine that in combination with the right thickness/thinness on a blade and a Convex grind, a Tsuchime finish could be an extra aid for good food release as well. But I don't expect a Laser thin, Full Flat grind blade with a Tsuchime finish to do well in regard of food release.

I have a knife from almost every maker and series of knives that JNS sells (Shuji Toyama, Kenichi Wada, Shigefusa, Kiyoshi Kato, Yoshikazu Tanaka). A Wakui and Munetoshi are the only ones I miss in my collection. I was very tempted to get me a Wakui workhorse knife, but didn't pull the trigger yet. I think I will wait until I visit JNS in Denmark again next year. I did have a Wakui 270mm Gyuto workhorse in my hands the last time I visited JNS. It's a hefty beast. It looked like it has just the right thickness and convex grind. It was really tempting, but I was already taking two other knives home with me.

@@chefknivesenthusiast Yes, the right thickness for food release without wedging when cutting dense vegetables (such as carrots and sweet potatoes) is around 3.5-4 mm above the heel. IMO food release and less food stiction are different terminology. I think Wakui Tsuchime Gyuto is a simple and functional knife, you should review it later.

I will have to check again. If you're right, it is a good example that a convex grind on a thinner blade does not have good food release and does have a lot of anoying stiction. Because the two thicker blades with a convex grind have amazing food release and hardly any stiction.

@@chefknivesenthusiast agree. The convexity is so shallow that it has little to no effect

​@@sacoto98Convexity on fine blades is not enough for food release but it lowers food adhesion. This subtle convex makes a huge difference when cutting potatoes. Real Full Flat grind gets glued on potato, I just hate it. I think for a good geometry design there is a balance. You either optimize for food release and accept some extra shoulder resistance or you optimize for shoulder resistance and accept food will not fall off. Both are good options as long as you don't hyper focus on one mechanism and forget there is another that also needs to be addressed.

What you describe sounds a lot like a Single Bevel knife (minus the Urasuki/Uraoshi) with a Hamaguri grind. It also sounds like a C-grind. I think in general, a flat bevel or side on a blade is terrible for food release. Anything gets sucked on to a flat surface. That's why convexity with the right thickness/thinness is the way to go.

I'm not a knife maker, so I'm not sure about how they exactly create certain grinds. But I think a hollow grind is done on a huge, vertical rotating stone (I think it is called a Kaiten Mizu Toishi). Then you have the Hikoki (horizontal rotating whetstone).You have belt grinders. But you should ask this question to a seasoned knife maker. I'm just a knife enthusiast.

The Kaeru has that sweet spot when it comes to thickness/thinness, in combination with a convex grind. Too thick and it will wedge through the harder stuff. Too thin and it will get stiction. The proof is in the pudding. It all depends on the tasks at hand in the kitchen. A convex/s-grind knife can be great for one task, but might suffer a bit with other tasks.

@@chefknivesenthusiast Well Mister I have to apologize because I didn't follow your advice (Kaeru), I instead got a Shiro Kamo 23 cm Gyuto in SG2, the one with the damas cladding ✨ Pretty hyped about the knife, even though it wasn't that sharp for various reasons (I can elaborate on this), but still it falls through onions pretty nicely... After a full reprofiling of the edge it will be great for sure ! Some people have said that the damas can become grippy, time will tell, at the moment it's really not a problem...

@@HellGatefr2 No need to apologize. Shiro Kamo knives are excellent starter knives as well. Good bang for your buck. Enjoy!

Especially agree with your conclusion.

To you and most most home cooks, food release is not a big issue. If you cut one 🥕 , it is no problem. Imagine you have to cut 100 🥕. It sticking to your blade all the time becomes very annoying and takes you completely out of your workflow. For you, good food release might not be important. To others, it's paramount. The Fujiwara came straight out of the box. He's infamous for his inconsistent fit & finish. His steel is great though!

@@chefknivesenthusiast makes sense, thanks. Do food release and force required correlate at all? A convex grind seems like it’d take a lot more force than a flat laser… is there a way to have your cake and eat it too? (Laser with release) LOOOOOVE my Denka now

By the way: effortless, laser like strokes are possible with thicker, convex ground knives if you use proper knife techniques. If you utilize the whole length of your blade instead of just chopping up and down. As you can see with the JNS Kaeru in this video. FYI: Just in case you do not already apply a controlled rocking, push-cut or pull-cut technique.

I hardly use much force with any knife. No matter the grind. Skill and technique come first. Always let the knife do the work, if possible. A flat grind/bevel will always create stiction. A thick blade with a convex grind will always create more displacement, perhaps even wedging. A convex grind combined with the perfect thickness and used with proper skill and technique...now that could feel like a laser with great food release.

Yes, that is the JNS Kaeru Kasumi SLD semi-stainless steel. What I failed to convey in this video, is that it is not just about a convex grind. A super thin knife with convex grind will still be very sticky as a too thick knife with a convex grind will be wedging. This knife seems to hit the sweet spot of the right "thickness + convex grind =- superior food release". I also have a TF Denka Nakiri and its food release is very decent and it's not that sticky. I wish there was such a list in existence. I for one did not came across it. Let me know if you do.

@@chefknivesenthusiast, that makes sense. The thinner the blade, the less material to create enough of a convex protrusion to encourage release. I'm going to have to pick up one of those knives. I've never seen such a list. Maybe it could be a group project in the Japanese Made Knives group. I'll bring it up in a post but you'll have to unblock me to participate (I really thought we'd put the disagreement behind us).

@JimCaputoMusic Go for it! It might be difficult to make such a list because a maker might not finish all his knives with the same grind. For example. I have seen lots of Nigara knives with a hollow grind, but also many with a Flat grind and convex grind.

@@chefknivesenthusiast, I started but I get what you're saying. It might have to get super specific and have plenty of asterisks. Also, I'm going to order a JNS Kaeru Kasumi SLD Gyuto 21 cm from Meesterslijpers. Is there a way to give you credit for the sale? I don't know if that's a thing there but I figured I'd ask.

@JimCaputoMusic No need for credits. You could add "say hi to Hendrawanto for me" if there is an option to do so. But the guys at Meesterslijpers know my worth. 🙏🏾 I'm pretty sure you're going to enjoy the Kaeru. It's a banger!

I used 4 ingredients per knife, each worth 25%. Other than that, I pulled the numbers out of my behind. But they are pretty accurate I think. I could have ranked them from number best to worst. Anyway, I think the footage speaks for itself basically. All cut ingredients became a happy soup.

I know. Please bear with me. I'm just a small creator, with only 2k subs, doing it all by myself, in my spare time, in the corner of my living room. I actually do have good mics. What I don't have is a good camera. I do it all with my phone and edit in iMovie. I try to make the best with the minimum of gear. The good mics I have can't be used with a phone. The input does not match. I will have to invest in a proper camera one day and in a perfect world make a dedicated room for youtubing one day. But for an amateur, I'm not making terrible quality videos. Give me some time to grow and evolve organically as a channel. It will get better every baby step at the time.

Hahaha. Good one. But no. I actually tested these three, and only these three different grinds on double bevel knives for this video. But indeed, for excellent food release: join the Ura side of the force.

If you're looking for a no nonsense workhorse, look no further than a Kaeru. But I also do love and appreciate all the craftsmanship that went into alll my other knives, even if the have shitty food release. I appreciate them for what they are. But yeah, I do agree with the sentiment of your comment.