Can a good knife cut hot food? How hot can it be?

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905870477

905870477

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Hi, recently I made some fried chicken and boiled meat, and I want to cut them when they are still hot.
But..would the high temperature damage the knife? I heard that for Yanagiba kasumi, rapid change of temperature will cause the knife to bent because of different curving rate of two metal, and some other knife may even annealing and not as hard as before.
So I wonder, what affect the ability to withstand high temperature and rapid change of it? Like Tojiro DP, or Kurouchi or three layer knife, or kasumi, do they(how they are forged) make a difference? or it depends on the metal like white paper or stainless?
For different knives, like Tojiro DP, Tojiro Kurouchi, or Masamoto kasumi Gyuto, or Takamura Migaki SG2 Gyuto, Takeda Aogami super, Can they cut very hot meat without damaging the knife?
 
The temperatures of food never get high enough to affect the metal like that.
Meats and foods right out of ovens, broilers, or boiling water are totally fine.
 
The tempering temperature for most steels is around 200 degrees Celsius, so speciality steels even higher. So, as already mentioned, there is no need to worry about cutting hot food as it is never warmer than 100 degrees.
 
I wouldn't think so. I'm not a metallurgist but the internal temp of the meats you're talking about are only going to be about 80°C to 90°C tops and that shouldn't be high enough to cause any structural change in the steel. Normally you would rest your food for a bit before carving and that would bring the internal temp down a bit also.
 
Good answers above. There are some steels that can be high temperature tempered for a pretty good hardness. So it's possible to make one that can stand poking around in coals or stuff like that even. For example elmax can be ran 500 c for 60 hrc. It becomes a little less "stainless" but imo it still behaves stainless.
 
Ah...thank you for these answers.....but the reason why I am worried is from a thread I saw, it saids:

"The bending of my kobayashi and masamoto happened during sharpening sessions in winter; I was sharpening the knives late at night in the kitchen with tap water running.
I exposed the blades to kind of "hot" running tap water directly on the knives and stones as my hand was cold. I recall that the blades became hot enough that I could not touch it with my fingers near the tip area but blades became cool quickly. So, during the sharpening sessions the blades went through hot/cold cycles until I noticed the bending. As hagane/jigane have different thermal expansion coeff., I have been under the impression that the hot water might have caused the bending.
Anyway, since the experience of the bending, I only use warm water in winter and never let the blades to become hot. I have never experienced any more bending of a blade since.
By the way, I don't do the long stoke...only section by section."

and the answer from Korin Mari is that
"The reason why this happens is because of a phenomenon called age hardening. Carbon will bend and warp after being forged due to the nature of the metal. Forgers resolved this problem by adding a thin strip of carbon to a thick piece of steel. Even if a knife is purchased in good straightened condition, both metals will naturally want to bend in opposite directions over time. There are knives that were poorly made and cannot be straighten well, and there are knives that can be straightened and used without a problem. However, it is pretty impossible for a knife to be completely straight and stay straight forever. All yanagi knives need to be straighten out by a professional every now and then. Some places offer this service for free, so you could try asking whoever you purchased from. Honyaki knives are MUCH harder (and scarier) to fix, so make sure whoever you ask to fix can do it well."...
But now I think I will try to cut these food...
 
Please note that Mari's response was about the knife composition in general being susceptible to warping, and not supporting the OP's theory that the water caused it.
 
I tend to avoid it - some steels (ZDP for example) are affected at far lower temperatures already, and I'd not trust the surface temperature of something out an oven or deep fryer, or something cooked in a heavy syrup, to be always limited to 100°C... or the internal temperature of something that has been in a pressure cooker or broaster. Edge cases, but why risk it...
 
I wonder whether high speed steels would be more heat resistant?

I'm thinking steels alloyed with W or Co like HAP40 and SRS15. Even VG10 has some Co in it.
 
LifeByA1000Cuts - you've got a point. I googled and found out that indeed ZDP steel is being tempered to only 100 - 150 degrees Celsius, so while one would not damage it by cutting hot food, it could indeed get closer than necessary.
 
Sorry but the temp of water is just not enough to do damage... and too hot to touch with fingers is like 60 to 80 degrees C. Not hot at all for a steel. So the steel should handle the thermal cycling very comfortably.

Also where is the info of the different coefficients of thermal expansion? I would suggest they are pretty close to the same... or at least close enough to make no practical difference.
 
The coefficients of the thermal expansion of the jigane and hagane are different - the stiffness of the sanmai blades is a direct proof + remember what happened to the 2 sanmai blades Ian Haburn accidentally mistook for monosteel stainless and put them in liquid nitrogen. The jigane contracts more upon cooling than hagane (at least for iron/carbon steel combination)
 
Some Stainless to carbon steel is a reasonable difference but iron and carbon are relatively similar.

Also, remember the degrees we are talking here for a 300mm blade with a 100 degree rise (or drop in temp) we are talking about a 0.4mm (K of 12E-6) increase (or decrease) in length so the difference between steels is a lot less... then take into account the fact that in the water example the rise in temp is probably only 50C at most... don't think it is a problem...

And sorry when I said for practical purposes I was referring to practical use of the knife... quenching is an extreme and the significant temp drops experienced during quench can place extreme stress on a blade as Ian's example proves. (Like we are talking a 1000C temp drop in seconds.... a lot difference than hot running water.
 
@malexthekid "too hot to touch with fingers" is very dependent on surface thermal capacity (if I can usually handle things being sauteed with my fingers - not dripping wet stuff and not fingers dipped into the oil, mind you - and am not a pro, what can people professionally used to heat take?), not necessarily initial temperature... but yes, steel SHOULD be a better heatsink than any fingers, on the other hand, it only takes a very shallow effect to mess with temper?

And who says we aren't talking "moved onto the cutting board with tongs, and cut with a rocking motion and not touching it"?
 
What heat you can handle doesn't change the stats on what causes burns... skim burns at a certain temp... now if you are previously scarred to hell then that may be different, however still isn't going to change the fact that food temps won't be anywhere near high enough to effect that..

Your product would be charcoal to be anywhere near those temps...

Remember medium rare steak is about 56C.
 
The external food temp may be higher in a very hot pan or oven, but I would assume it would still be limited to pretty close to 100 C until all of the water has boiled off. I'd be surprised if this was hot enough to ruin the temper.
 
Nemo said:
The external food temp may be higher in a very hot pan or oven, but I would assume it would still be limited to pretty close to 100 C until all of the water has boiled off. I'd be surprised if this was hot enough to ruin the temper.
Click to expand...

Even if the outside layer (1mm or so) was 150C I would doubt that it would have the ability to heat the steel to anywhere near that temp... when the rest of the meat is a heat sink pulling that temp down too...

Heck I would think that after a minute or two out of the pan there would be a significant drop in temp of the surface.
 
malexthekid said:
Even if the outside layer (1mm or so) was 150C I would doubt that it would have the ability to heat the steel to anywhere near that temp... when the rest of the meat is a heat sink pulling that temp down too...

Heck I would think that after a minute or two out of the pan there would be a significant drop in temp of the surface.
Click to expand...

Not to mention that the reat of the knife is a heat sink, with likely excellent thermal conductivity.
 
OK, pester me until I remember to take a FLIR when I cut something fresh out of a pan....
 
Not sure as to definite causation, but a coworker used an old suji (vg10) to impale a roast (was left inside for 5m), and then chop spring onions, which caused massive microchipping along the edge...
 
I keep reading this thread's title and finding it really irritating. I'm going to argue that, with possibly a few extremely narrow exceptions*, if the steel / heat treat is so marginal that hot food can affect the knife's properties it's NOT A GOOD KNIFE! Just like we expect a good profile, grind, etc. on a good knife we should be able to expect a usable steel & heat treat.

(*Only exception to this that is coming to mind is an extremely specialized sushi knife expected to only work with refrigerated raw fish.)

Sorry. Continue your speculations, I'll shut up.
 
The OP asked a perfectly legitimate question that has been addressed adequately. I don't understand your irritation.
 
@Yet another dave, by the same argument you could say carbon steel doesn't make a good knife since you can't be careless with citrus fruit or vinegar pickled things with it.
 
Sigh, I'm probably digging a deeper hole, but I'll try to explain....


Benuser said:
The OP asked a perfectly legitimate question that has been addressed adequately. I don't understand your irritation.
Click to expand...

OP wanted to care for their knives, that is admirable. The practical, or physics, question was analyzed, thought through, and an interesting discussion. If we get follow up FLIR measurements that would be incredible.

But the title implies a meta-, or philosophical, question *AND* answer. Rephrasing it it can be read as, "Can a kitchen knife that can be damaged by hot food be good? Yes." To me, the answer should be "No." (With possibly a few very narrow exceptions.) It grates to think something so fundamentally unfit for purpose could be put in the good category.


LifeByA1000Cuts said:
@Yet another dave, by the same argument you could say carbon steel doesn't make a good knife since you can't be careless with citrus fruit or vinegar pickled things with it.
Click to expand...

I suppose it's arbitrary, but that doesn't fall in the same category at all for me. First, you can cut citrus, etc. with carbon steel by being careful and carbon steel brings advantages in sharpness, sharpening, and edge geometry. So, to me, it falls in the category of "trade-off". Not unlike sharp versus relaxed sharpening angle or light weight and thinness behind the edge versus heavy and sturdy are tradeoffs to make depending on expected use.

Obviously my comment was controversial and ruffled feathers, I apologize.
 
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