Decreased food stickage

Robert Erickson

Robert Erickson

Knifemaker / Craftsman / Service Provider
Joined
Feb 2, 2014
Messages
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I've made a few chef blades, all with a FFG and they slice well but food sticks quite a bit. What bevel characteristics will best reduce food stickage on a chef blade? And what is your technique for accomplishing it?
 
The one thing that I have seen that I really like on some custom knives is a compound grind. You get a thin edge and then the maker uses a 36" radius platter to get a larger hollow grind. Thin and releases the food.
 
there is a compromise that has to be made. a knife that is nice and thin behind the edge is going to be stickier but cut better than a knife that is thicker behind the edge. the thicker knife will release food better but won't cut as nice.
 
I do a hybrid flat/convex grind. I start with a full flat to get almost the desired thickness behind the edge then convex the whole blade. So the blade has grind geometry kind of like an almond. But like Bill said its is still a trade off. Between thick and thin
 
Bill said it all
when building a custom piece get all the info on the user needs that you can and build to that need
if making a non order knowing what the blade shape is 99% used for and tune it to max that use
nakiri oftn have stiction issues but heavy chefs do not
one thing overlooked is the finish of the blade. things like granton divots and holes in the blade might help a little (im not so sure tho ) they also bring up other issues liek cleaning and honing over the life of the blade
 
Brian Avila said:
The one thing that I have seen that I really like on some custom knives is a compound grind. You get a thin edge and then the maker uses a 36" radius platter to get a larger hollow grind. Thin and releases the food.
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I'd like to see how they do that. I guess go FFG and then hollow a certain amount near the edge. Sounds tricky.
Bill Burke said:
there is a compromise that has to be made. a knife that is nice and thin behind the edge is going to be stickier but cut better than a knife that is thicker behind the edge. the thicker knife will release food better but won't cut as nice.
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I imagine it depends on the exact purpose of the knife too ie Slicing veggies vs de-boning chickens.
LP Mac said:
I do a hybrid flat/convex grind. I start with a full flat to get almost the desired thickness behind the edge then convex the whole blade. So the blade has grind geometry kind of like an almond. But like Bill said its is still a trade off. Between thick and thin
Click to expand...
What edge thickness do you start your convex?
 
butcher_block said:
Bill said it all
when building a custom piece get all the info on the user needs that you can and build to that need
if making a non order knowing what the blade shape is 99% used for and tune it to max that use
nakiri oftn have stiction issues but heavy chefs do not
one thing overlooked is the finish of the blade. things like granton divots and holes in the blade might help a little (im not so sure tho ) they also bring up other issues liek cleaning and honing over the life of the blade
Click to expand...

I would imagine anything that reduces the surface area touching the food would help ie Damascus etching?
 
The side closest to the chef can be fully flat ground to help keep thin behind the edge. The opposite side is best flat ground about 2/3rds up the blade face, then the TOP of the blade is convexed, not the edge. This causes the top of the flat grind to be the thickest part of the bevel. Also blade thickness and distal taper need to be taken into account. Like Bill said it is a trade off, this general info is what has worked best for me for a general purpose chef knife, other more specific tasked knives have different geometry.
 
As someone now retired who spent most of my life behind the rail preparing food, I feel pretty confident in saying that granton divets make little to no difference for cutting meats/cheeses/fats etc. Not a whole lot else sticks really.
 
Kitchen knives are fairly mysterious to me. I have two custom Santokus, one of thick stock with an aggressive hollow grind. The whole thing is pretty thin aside from the spine. The other is a full flat grind, really thin stock (sorry, I don't have the actual stock dimensions but one is about twice as thick as the other).

I'd rather cut leather than veggies but my wife swears by the large hollow. She cited stiction as a deciding factor too. That and ergos.
 
I have used what i would call an "S" grind on a couple of blades and by all accounts, they worked well. What I did was a full flat grind until the edge was right under 1mm. then a second flat grind from about 2/3 up down to the edge. After that, i convexed the edge up about 3/8 and then used my 72" platoon to do a little holllow right below that shoulder at the 2/3 point. I think blend that shoulder, the hollow and the top of the convex edge by hand sanding. Did that make any sense?
 
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JMJones said:
The side closest to the chef can be fully flat ground to help keep thin behind the edge. The opposite side is best flat ground about 2/3rds up the blade face, then the TOP of the blade is convexed, not the edge. This causes the top of the flat grind to be the thickest part of the bevel. Also blade thickness and distal taper need to be taken into account. Like Bill said it is a trade off, this general info is what has worked best for me for a general purpose chef knife, other more specific tasked knives have different geometry.
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Makes sense I'll try this next time. I've done some looking and it looks like a number of Japanese chef blades are chisel ground. I would imagine this would help too.
jdm61 said:
I have used what i would call an "S" grind on a couple of blades and by all accounts, they worked well. What I did was a full flat grind until the edge was right under 1mm. then a sedan grind from about 2/3 up down to the edge. After that, i convexed the edge up about 3/8 and then used my 72" platoon to do a little holllow right below that shoulder at the 2/3 point. I think blend that shoulder, the hollow and the top of the convex edge by hand sanding. Did that make any sense?
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I'm not familiar with a "sedan grind" is that a hollow grind? So from the edge you have a concavity then convexity? Thanks!
 
Not sure how spellcheck got "sedan" out of second but correction made. LOL
rcetroy said:
Makes sense I'll try this next time. I've done some looking and it looks like a number of Japanese chef blades are chisel ground. I would imagine this would help too.

I'm not familiar with a "sedan grind" is that a hollow grind? So from the edge you have a concavity then convexity? Thanks!
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LOL jdm61! You've gotta love spell check. Maybe we'll have to name your technique the sedan grind. :-)
 
Good answers above, I like what Bill said- it's true, always a tradeoff. My technique has been to FFG down to about .040", heat treat, finish ffg down to .030" or so, then grind the bottom 1/3 of the blade slightly convex down to .007" or so at the edge on a chef that will be used for mostly vegetable prep. Works ok, but it does lean toward the "thin/slices better" side of the compromise. I would rather have the occasional zucchini slice roll off the cutting board, but be able to quickly, safely, and accurately prep food like only a good thin sharp edge will do.
 
I'm really happy that this discussion is happening. I literally lie awake at night thinking about kitchen knife geometry.
What is the word on the type of geometry that Murray Carter and others use, where the blade is very thin and has only a very narrow grind? How does this do with stiction?

- Chris
 
^ It's nice to get input from the pros

I'm not a kitchen knife guy, but I've cut my share of potatoes.

My favorite knife for that is a cheap carving knife that I modified with a thin shallow hollow grind. The short height and the shallow hollow pops them off pretty reliably. Next to that, I have a thin 6" Japanese Santoku with that "S" grind that is pattern welded that releases pretty well while being insanely (flexes over a thumb nail) thin.

I've heard some people swear by the short deep hollow grind on cheap cutlery and stuff like "Cutco" for food release. People like my mother don't seem to care if it cuts well (it's going to be dull as hell anyway) and the food release is pretty reliable, even on stuff like moderately soft cheese.
 
dont get wrapped up in the chisel grind hype total edge angle is the same (20 degrees is 20 degrees no matter if its ground 50/50 or 0/100 ) they wedge and cut curves when doing cuts that are not slices
S grind is kind of funny thing and im not all together sure its worth the work (i have a tester waiting on one ) but if you think flat ground and lightly convexed edge then go back with one of nates 48" plattens to hollow out behind the edge
Carter grinds his knives thin but the short grind hight helps pop food off as does that forged finish on the flats just above the main grind.

funny how many things come into play on such a "simple" knife
 
Noob here, but the knife I use to for things that normally result in stiction does have divots and personally I think they do help.

The reasoning behind this, amongst other things, is based on my experience with Velveeta cheese, which I eat quite a bit of. Slicing this cheese was always a pain in the ass as it'd create a serious air tight grip on the bevel. I don't get that as bad now that I use a knife with the divots.

To me, it's those air tight finishes that cause the problem, not the stickiness of the food.

What about a flat grind 1/3 the way up and an as forged finish the rest of the way? Any possible sanitary issues?
 
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