Maximizing Edge Retention – What CATRA Reveals about the Optimum Edge

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I have had carbon edges notably degrade through a handful of tomatoes... as in, would easily bite the first and would be erratic on the fifth... sure it is a myth? Or is there reason to believe the tomato skin is just so damn tough it works as an anti-strop?
 
I've had similar happen. I suspect 2 possibilities, either there was a burr/wire edge or the edge was too polished. For me my edges seem to last longer on tomatoes with lower grid. I used to do 6000 and 4000 feels sharper longer. My plan is to try 2K and 1K next or even DMT 600:bigeek:
 
In one of salty's videos he talks about moving his edgeto keep it (razor) sharp...on a single tomato... :(
 
LifeByA1000Cuts said:
I have had carbon edges notably degrade through a handful of tomatoes... as in, would easily bite the first and would be erratic on the fifth... sure it is a myth? Or is there reason to believe the tomato skin is just so damn tough it works as an anti-strop?
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I go through a lot of tomatoes (and pickles) with my carbon steel knives and they stay peak sharpness for a month or two at least. Sounds more like you're experiencing a wire edge.
 
My FKH (SK-4 @ 58 HRC) lasts through the entire canning season without touching anything more than a stack of slack newsprint and I don't squash my tomatoes. Then again, I am not trying to chop them either. Push/pull/slice is fine by me. No need, for me, to rapid chop a bushel of tomatoes. (Edge is that left from an Ikarashi fwiw.)
 
LifeByA1000Cuts said:
I have had carbon edges notably degrade through a handful of tomatoes... as in, would easily bite the first and would be erratic on the fifth... sure it is a myth? Or is there reason to believe the tomato skin is just so damn tough it works as an anti-strop?
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Tomatoes have plenty of acid that degrades a knife edge rather rapidly compared to other veggies. I can tomatoes every year and you can definitely notice degradation in a knife edge after several tomatoes. That's not to say the knife is immediately dull but the degradation is definitely noticeable. The acid in tomatoes will definitely kill that fresh off the stone edge as fast as anything you will cut.
 
K813zra said:
My FKH (SK-4 @ 58 HRC) lasts through the entire canning season without touching anything more than a stack of slack newsprint and I don't squash my tomatoes. Then again, I am not trying to chop them either. Push/pull/slice is fine by me. No need, for me, to rapid chop a bushel of tomatoes. (Edge is that left from an Ikarashi fwiw.)
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Not with a 58Hrc knife or your not canning that much, especially tomatoes.
 
HRC_64 said:
How can you resist the urge to sharpen anything for that long :rofl:
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Not as long as you might think. I grow two to three tomato plants and two cucumbers. I don't grow a forest. And I have stone tester knives for daily sharpening. (Tojiro ITK and Zakuri B#1)
 
If that's all you grow then you don't can that much. I've got 14 tomato plants alone. Those "baskets" you speak of must be pretty small. I'm talking about doing several cases of Juice quarts and another several cases of diced tomato quarts on top of what we use fresh. I can enough tomatoes to last us through the rest of the year and have plenty to give to family and neighbors.
 
yeah, even our season is like 4-6weeks and its not california
or somewhere with proper mediterranean climate
 
bahamaroot said:
If that's all you grow then you don't can that much, I've got 14 tomato plants alone. Those "baskets" you speak of must be pretty small. I'm talking about doing several cases of Juice quarts and another several cases of diced tomato quarts on top of what we use fresh. I can enough to last us through the year and have plenty to give to family and neighbors.
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Didn't mean to imply it was hundreds of cans of tomatoes just that the edge isn't going to become completely useless on tomatoes after just a few which was earlier implied. Apologies, I will try to be more exact in the future.
 
This is a perfect demonstration of why what Larrin is doing is so useful and interesting. All the talk about “real life” use and cutting tomatoes for days, month years..... Precisely why scientific method and experimentation is so important. I am not doubting any of the participants and believe that all are truthful, the problem is that until you define what “sharp” is and what a generic tomato is, besides all the other parameters you can’t compare these things.
 
It would be fun to set up an experiment with a sharpness tester and some common acidic foods. Maybe someone has even done it already.
 
Barmoley said:
This is a perfect demonstration of why what Larrin is doing is so useful and interesting. All the talk about “real life” use and cutting tomatoes for days, month years..... Precisely why scientific method and experimentation is so important. I am not doubting any of the participants and believe that all are truthful, the problem is that until you define what “sharp” is and what a generic tomato is, besides all the other parameters you can’t compare these things.
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Agree, the large amounts of tomatoes I cut were not vine ripe, but my carbons could go through many slicing and dicing. When I worked in a large banquet Hotel we used a machine to dice tomatoes for lomi salmon. It was terrible the lomi came out mushy. Only a sharp knife makes good Lomi Salmon.

All I can say is cut tons of acidic foods with carbon knives over 25 years and never crossed my mind that acid was dulling them. Thin geometry and easy to sharpen carbon worked better than my stainless knives. My knives were the most borrowed for special jobs, sometimes I would come back from setting up a banquet and find a chef using my knives to clean & portion fish and meats than ran out on the front line. They would go straight to my carbons because I kept them sharp. Was a total carbon junky only later found out about user friendly powder steels like R2 and SRS15. Others ,G3 AEB-L much better than any stainless I had ever used before.
 
Larrin said:
It would be fun to set up an experiment with a sharpness tester and some common acidic foods. Maybe someone has even done it already.
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That would be difficult to calibrate to real-world conditions, since some of us are apparently seeing quick degrading of the edge with acidic food, and others aren't. I don't cut cases of tomatoes or lemons at a time, but I have gone through a couple dozen plum tomatoes with my carbon knives when making a huge pot of tomato or chili sauce, without noticing any decline in cutting ability.

Also, I'm having trouble imagining a reaction that would actually remove or re-shape metal at the blade edge in a relatively short amount of time, say an hour or two of heavy tomato prep. This isn't hydrofluoric acid we're talking about here.
 
Barmoley said:
This is a perfect demonstration of why what Larrin is doing is so useful and interesting. All the talk about “real life” use and cutting tomatoes for days, month years..... Precisely why scientific method and experimentation is so important. I am not doubting any of the participants and believe that all are truthful, the problem is that until you define what “sharp” is and what a generic tomato is, besides all the other parameters you can’t compare these things.
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I agree, it would take a much more scientific method to clarify any of this, too many variables at play here.
The only thing I can say for certain is if you cut a bushell or so of tomatoes you will definitely feel the degradation of any edge be it carbon or especially a soft stainless. Tomatoes are that acidic. I'm in know way saying that it will render the knife edge near useless but there will be a major difference between the starting edge and the ending edge just from the acid.
 
Paraffin said:
Also, I'm having trouble imagining a reaction that would actually remove or re-shape metal at the blade edge in a relatively short amount of time, say an hour or two of heavy tomato prep. This isn't hydrofluoric acid we're talking about here.
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But we are also only talking about remiving or reshaping or chemically changing a fraction of a micron of steel.
 
I don't think it is acidic food in general I think it is tomatoes specifically, especially really ripe tomatoes. When the skin is tough and there is no support. This doesn't happen with tomatoes that are not soft, those you can cut for a while without noticing edge changes. It is unlikely to be caused by acid, tomato skins are tough and the fruit is soft, so tiny edge changes are very noticeable.
 
Paraffin said:
That would be difficult to calibrate to real-world conditions, since some of us are apparently seeing quick degrading of the edge with acidic food, and others aren't. I don't cut cases of tomatoes or lemons at a time, but I have gone through a couple dozen plum tomatoes with my carbon knives when making a huge pot of tomato or chili sauce, without noticing any decline in cutting ability.

Also, I'm having trouble imagining a reaction that would actually remove or re-shape metal at the blade edge in a relatively short amount of time, say an hour or two of heavy tomato prep. This isn't hydrofluoric acid we're talking about here.
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Well first we should look at a relatively extreme case just to see what could realistically occur. Such as lemon juice immersion of the edge and sharpness tested after 1, 3, 10, 30, 100, 300 minutes. For example, if there was a measurable loss of sharpness after 1 minute that would confirm that corrosion affecting the edge is not only possible but relatively likely with corrosive foods. On the other hand if after 300 minutes there was no drop in sharpness that would indicate that loss of the edge through normal cutting and cleaning would be unlikely. You’d need a good sharpness tester.
 
those that dont believe a 58hrc knife can last through blasting away tomatoes is cause you're not that good at sharpening despite what you might think and/or your technique is the culprit (too much board contact/force)
 
Larrin said:
Well first we should look at a relatively extreme case just to see what could realistically occur. Such as lemon juice immersion of the edge and sharpness tested after 1, 3, 10, 30, 100, 300 minutes. For example, if there was a measurable loss of sharpness after 1 minute that would confirm that corrosion affecting the edge is not only possible but relatively likely with corrosive foods. On the other hand if after 300 minutes there was no drop in sharpness that would indicate that loss of the edge through normal cutting and cleaning would be unlikely.
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Good idea.

The only confounding factor I can think of is rhat there may be an interaction between the acid and the abrasion on the edge caused by cutting.
 
Barmoley said:
I don't think it is acidic food in general I think it is tomatoes specifically, especially really ripe tomatoes. When the skin is tough and there is no support. This doesn't happen with tomatoes that are not soft, those you can cut for a while without noticing edge changes. It is unlikely to be caused by acid, tomato skins are tough and the fruit is soft, so tiny edge changes are very noticeable.
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It's definitely the acid in the tomato. All of the tomatoes I cut when canning have already been blanched and peeled by pulling the skin off before cutting. No skin is ever cut and I cut the tomatoes in hand over a 1/2 sheet so board contact is not a problem either.
 
Nemo said:
Good idea.

The only confounding factor I can think of is rhat there may be an interaction between the acid and the abrasion on the edge caused by cutting.
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But doing both at a time would leave you unable to determine the individual effects. If acid alone didn’t affect the edge a second experiment could be cutting some fixed material (such as rope as you said) both with and without the acid. But the wear from the rope may overwhelm the effect of corrosion.
 
Larrin said:
Well first we should look at a relatively extreme case just to see what could realistically occur. Such as lemon juice immersion of the edge and sharpness tested after 1, 3, 10, 30, 100, 300 minutes. For example, if there was a measurable loss of sharpness after 1 minute that would confirm that corrosion affecting the edge is not only possible but relatively likely with corrosive foods. On the other hand if after 300 minutes there was no drop in sharpness that would indicate that loss of the edge through normal cutting and cleaning would be unlikely. You’d need a good sharpness tester.
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This would be a great test that would really show how much food corrosion affects edges. Some effect has to exist, but how severe and how rapid are very interesting questions.
 
panda said:
those that dont believe a 58hrc knife can last through blasting away tomatoes is cause you're not that good at sharpening despite what you might think and/or your technique is the culprit (too much board contact/force)
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Never said that I dont believe a 58hrc knife can last through blasting away tomatoes. Only that that knife will not last a whole season of canning something like tomatoes with only stropping on newspaper. After several hours of cutting up nothing but tomatoes there will be a definite difference in the edge. And it won't survive a whole SEASON with just news stropping regardless of your sharpening skills. And mine are quite good rather you believe it or not.
 
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