# Poll: Does blade surface roughness affect on food release? What surface finish releases best?



## Knife2meatu (May 13, 2019)

I only have beater knives whose appearance doesn't matter to me. After I'm done thinning, if I want to minimize food sticking:

Would there be some advantage to refining the scratches on the large thinned area?

If so, is the there some regular improvement as grit increases?

Or is there some approximate point past which gains are minimal?


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## refcast (May 13, 2019)

Best release for me is when its a very fine kasumi type thing. Worst release is coarse grit kasumi, then burnished mirror polish. If you just take natural stone grit to a burnished mirror polish, or let it patina, then its okay and actually very good. Burnished is when you mirror polish at high speed with dulled grit.


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## Carl Kotte (May 13, 2019)

Good topic! I will follow this closely. No relevant input re topic though.


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## Nemo (May 13, 2019)

With synths, I have had best food release with a 2-4k polish. Anything more seems to be detrimental to food release.

I have a soft uchi which also gives good food release.


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## metamorpheus (May 19, 2019)

Too fine of a polish and wet veggies suction onto the blade road. Too coarse gets grabby on food and the knife wont drop through as smooth. Behind the edge is the most important. Better to have a fine kasumi with a litte texture to channel the water through the grooves.


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## mikaelsan (May 21, 2019)

depends on what your cutting, i prefer 400-2000.
i test by rubbing my finger on the knife and seeing how much resistance the finish gives


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## bahamaroot (May 21, 2019)

Geometry has more effect on release than finish.


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## Nemo (May 21, 2019)

bahamaroot said:


> Geometry has more effect on release than finish.


Agree with this.


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## Knife2meatu (May 21, 2019)

I'm sure that's right. But...

If I'm asking whether racers are achieving better times around a circuit with soft or hard suspensions, somebody saying that their engine has more to do with the results than do the shocks may be right -- but it doesn't seem to help me decide how to tune my suspension.


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## Kippington (May 21, 2019)

*"Yes. It does influence food release; but the best grit depends on the food stuff.'*

Rougher surfaces tend to be better overall.
However, some slippery foods will slide off mirror polished knives. It's very noticeable with cucumber slices.

On a semi-related note, rough finished carbon has a higher chance of rusting over a polished finish.


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## scott.livesey (May 21, 2019)

I have found that the food is more important than finish of the blade. I am slicing potatoes. Nothing is sticking. I finish the bag and get some more potatoes to slice. Same brand, bought same day in the same store. Every slice of potatoes from bag #2 stuck. Washing the knife did not change sticking. Could someone explain this, which happens all the time.


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## Kippington (May 21, 2019)

scott.livesey said:


> I have found that the food is more important than finish of the blade. I am slicing potatoes. Nothing is sticking. I finish the bag and get some more potatoes to slice. Same brand, bought same day in the same store. Every slice of potatoes from bag #2 stuck. Washing the knife did not change sticking. Could someone explain this, which happens all the time.


Maybe related, cutting potatoes straight down the middle will sometimes develop a curve on both cuts that hug the sides of the knife, even if the grind is nicely concave. S-grinds have far better release success rates in these cases.
It's very noticeable on potatoes which have been soaking in water, as I guess the outside has expanded with the added water content.


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## Carl Kotte (May 22, 2019)

bahamaroot said:


> Geometry has more effect on release than finish.



That is correct, but is it relevant to the topic under discussion? Does your claim answer the original question?


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## Carl Kotte (May 22, 2019)

Knife2meatu said:


> I'm sure that's right. But...
> 
> If I'm asking whether racers are achieving better times around a circuit with soft or hard suspensions, somebody saying that their engine has more to do with the results than do the shocks may be right -- but it doesn't seem to help me decide how to tune my suspension.



Word!


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## Nemo (May 22, 2019)

Carl Kotte said:


> That is correct, but is it relevant to the topic under discussion? Does your claim answer the original question?


Maybe not but it is relevant information.


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## bahamaroot (May 22, 2019)

Carl Kotte said:


> That is correct, but is it relevant to the topic under discussion? Does your claim answer the original question?


It's very relevant and does answer the question. If you have a good geometry it doesn't matter what the finish is.


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## Jville (May 22, 2019)

bahamaroot said:


> It's very relevant and does answer the question. If you have a good geometry it doesn't matter what the finish is.



Ive always leaned towards agreeing with this, but im dealing with a new knife now thats a bit sticky ootb. Its mirror polished with a "workhorse grind." I have anothet knife from the same maker with a little less polish and also it has developed more patina, with more gray surface area. It is quite similiar in grind, but has much better food release currently. I was told by maker, it should calm down after it patinas more. So perhaps, finish might play a bigger role than sometimes given credit. I think the first knifes food release also may have improved after it developed a rich patina, but i cant be sure. I wasnt paying as close attention to it. Also it wasnt as highly polished to begin with. I will pay attention with this knife and report back.


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## mikaelsan (May 22, 2019)

sure it matters, with some grinds you have more contact with the ingredient your cutting, here the difference will be more noticeable, with some grinds you will have less and the difference will be less noticeable, that doesn't mean the difference is not present. 
Besides when your dealing with a knife where it matters, why not try and optimize it, instead of just dismissing the knife for its grind. I got a nakiri, thin thing wide bevel and a polished buffed finish, things improved massively after i roughed up the bevel with my akamusa, its not as pretty though.


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## rick alen (Jun 2, 2019)

Nemo said:


> Maybe not but it is relevant information.



Listenng to comments I think the most relevant here is, "What kind of finish is the most slippery on what foods"?


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## ojisan (Jun 4, 2019)

My understanding is that mirror finish is the worst generally but when you cut thicker narrower slices, mirror finish might release better.

Things easily stick to a blade when the surface is smooth (like a suction cup), but when a slice is heavy and (the contact surface is) small enough, it slips and drops off the blade (water helps?). Kasumi finishes generate some frictions and that seems to prevent from slipping. However, I assume it's very hard for anyone to tell actual conditions that mirror finish starts working better.

For the ultimate geometry, buy a Glestain. It's just awesome.



A comparison test:


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## Kippington (Jun 7, 2019)

ojisan said:


> My understanding is that mirror finish is the worst generally but when you cut thicker narrower slices, mirror finish might release better.
> 
> Things easily stick to a blade when the surface is smooth (like a suction cup), but when a slice is heavy and (the contact surface is) small enough, it slips and drops off the blade (water helps?). Kasumi finishes generate some frictions and that seems to prevent from slipping. However, I assume it's very hard for anyone to tell actual conditions that mirror finish starts working better.
> 
> ...



Thicker slices will always fall off easier due to the extra weight, plus the food balance-point being further from the blade.
Mirror polish only helps with slippery food.
The biggest factor tends to be the surface area of the blade in contact with the food. There's also the food getting thrown out to the side due to a fat grind. The following knife had a really fat grind as I was testing different things:


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