How Acidic Food affects Sharpness

you can try for yourself. take a Stanley blade and put a drop of Heinz ketchup on it. after the night the red ketchup has turned brown, later it is black. days later there are black spots (rust!) around the drop. even later ketchup mushrooms pop up next(!) to the drop. first they are red and you start wondering wth. eventually they turn black themselves wtf.
 
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Most of my cooking knives are high carbon steel that I inherited from my father, who was a professional cook and eventually sous chef for over 30 years.

With the exception of one that I bought myself, they all have the original edges put there by my father (or by the factory) and all I've ever had to do to keep them sharp is run them across a sharpening rod. All of them are stained but, unlike my expensive folders, I like that look on my cooking knives.

All I do after I use them, whether to cut meat or lemons, is to wash them and then wipe them dry. That should be enough to preserve them long after I'm dead and the knives are passed on to my son.
 
I wasn't writing about maintaining carbon steel knives or how long they last as much as I was writing about sharpness.
 
Larrin said:
I wasn't writing about maintaining carbon steel knives or how long they last as much as I was writing about sharpness.
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I read the article and understand the point that you were making.

My point was that all of my cooking knives stay sharp simply using a sharpening rod, whether made w/high carbon steel or not, by just washing and drying them after use and that whether you cut lemons or any other acidic food w/them really doesn't matter, especially considering that most of my knives are make w/low grade high carbon steel.
 
Nice work. Why fit a curve to 3 test points rather than a series of straight lines, or not connecting them at all?
 
brownshoe said:
Nice work. Why fit a curve to 3 test points rather than a series of straight lines, or not connecting them at all?
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The real behavior is rarely straight lines, and while it may be slightly off to use the smoothed lines it’s probably closer. Without lines it is more difficult to interpret the figure.
 
You don't draw curves in other plots where you have more data; you do straight lines. Personally, with three test conditions spanning an order of magnitude...no lines :)
 
It's standard in scientific literature to do curves. I don't see what the big deal is.
 
Larrin said:
I did a small study on the effect of acidic food on sharpness. This has been a commonly debated topic among kitchen knife enthusiasts. Is a carbon steel knife going to do okay with lemon juice?

https://knifesteelnerds.com/2019/01/21/does-acidic-food-affect-edge-retention/
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:) Thanks for the study ! Interesting and good to have a scientific experiment that supports my totally non-scientific , informal impressions of stainless vs non stainless seeming to need slightly more frequent touchup when using in corrosive environments .
 
Larrin said:
It's standard in scientific literature to do curves...
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You have too few points and too wide a range to characterize the curve you assume to be correct. It's often called "expectation bias" and is a common human trait. It's one of the reasons for independent review of a proposed experiment and of the final results.
 
The "curve" is minimal!!!!! It is a miniscule "curve"!!! The majority of the chart shows a straight line! So what if the curves, though slight as they are, are "interpreted"?? Anyone looking at the chart can come up with a pretty damn good representation of what is going on. Sure, one "could" repeat the experiment over and over and over and over to get a more accurate data set, but it's not like he is trying to patent the test!

I've been critical of Larrin in the past (he knows!), but geez!
 
I believe that the sharpness loss occurs through an increase in edge roughness rather than primarily through rounding of the edge like in slicing.
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Some people sharpen their metal working files by placing them in an acid bath.
I'm just saying . . .
I suppose you have proved acidic foods damage / dull very sharp edges.
In the same breath I submit my Little Monster (Japanese Plain High Carbon) at this Link>>>>; go there and page down (the post was not all about that one knife).

The Little Monster stayed literally hair whittling for over a year and "dropped" to just shave sharp during the next six months (a year and a half total with zero sharpening, no stropping and of course no sharpening rod or steel).
The knife was used daily exclusively by myself (no one else used it is what I mean). Nearly every one of those days I sliced a few slices or wedges off a lemon or lime or both. With my dinner I almost always have carbonated water and usually squeeze the lemon or lime or both into the water . . . often having a second or third serving (it's a small glass). The knife often sits on the counter with the lemon juice on it until I am finished with dinner.

The other foods the knife cuts are in your list; especially fresh oranges, lots and lots of apples, tomatoes etc.

So . . . given the right cutting board (a far more critical edge preserver) (see my link) . . . acidic food has an effect . . . the effect is so minuscule as to be unnoticeable in the real world.

Oh and . . . can the 20° per side . . . embrace The Little Monster's 10° or 12° per side for peace and contentment. ;)
40° inclusive ? ? ? . . . madness . . . just asking for a sucky cutting experience. :) :p
 
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Thank you for sharing your experience, Wowbagger.
 
DocJD said:
Is also to nitpick at someone's useful efforts whilst failing to improve upon them in any meaningful way . :rolleyes:
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His experiments and results are neat and interesting. Like you I "liked" his post and hope he continues. Since the author is a scientist and the line drawn from 3 points is essentially an experimental conclusion, pointing out a difficulty is trying to "improve upon them in [a] meaningful way".
 
brownshoe said:
His experiments and results are neat and interesting. Like you I "liked" his post and hope he continues. Since the author is a scientist and the line drawn from 3 points is essentially an experimental conclusion, pointing out a difficulty is trying to "improve upon them in [a] meaningful way".
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Maybe it is sometimes helpful to point out shortfalls in methodology . But useful experiments need not be so rigorous as to be never completed without substantial funding . :confused:

It is always easier to criticize than to create ! ;)
 
brownshoe said:
His experiments and results are neat and interesting. Like you I "liked" his post and hope he continues. Since the author is a scientist and the line drawn from 3 points is essentially an experimental conclusion, pointing out a difficulty is trying to "improve upon them in [a] meaningful way".
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Nobody ever said that every point along the curves represented tested, verified, and valid datapoints. And as you know from self-reflection, nothing in life is perfect, even if it looks perfect on the surface to you.
 
I welcome any suggestions for improvement. I may not take them all. :)
 
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