How sharp should your kitchen knives be?

Patrice Lemée

Patrice Lemée

Joined
Aug 13, 2002
Messages
5,703
Do they really need to be razor (or more) sharp? I saw something on TV about a place near here that sells high end kitchen knives and also does the sharpening. He was showing the TV host how this one knife was slicing through a carrot like it was how butter.
I could sharpen my kitchen knives to this extreme but I remember a few times that if they were that sharp, I would be missing if not a digit, at least part of it. They are still sharp but do they need to be scary sharp?
 
This is one of those "How many angels can we get dancing on the head of a pin?" questions. I like my knives sharp. In particular there should be no control issues cutting carrots and onions,or you'll windup cutting yourself. The edge should "bite" with little to no pressure. Beyond that, the knife should be properly designed for the task. Most kitchen cutting requires a thin blade - you're slicing, not splitting.

If my knife doesn't perform effortlessly, I steel it. If that doesn't help, I sharpen it - on paper wheels.
 
I think if it was me using it, I'd want it scary sharp. For someone else, I'd sharpen it a bit less if they're not used to sharp knives.

For example, I sharpened my aunts kitchen knives once, and at the next party, 3 people cut themselves while cutting cheese.
 
Sharp knives are less dangerous than dull ones, we all know. For kitchen use, a good knife should be able to make thin slices of a ripe tomato.
Faiaoga
:cool:
 
IMHO, balance getting the finest sharpest edge with maintaining that edge. I try to keep my knives as sharp as possible and use them on an end grain cutting board. I know the knives are very sharp, so I follow all the safety rules and slow down. My slicing cleaver[Aldo's 1084, hardened and tempered to Rc61-62, edge is 18degree total angle] will slice tomatoes thin with just it's weight.
cleaver2.jpg
I also let the grandkids use these knives under close supervision, so they can learn knife skills with proper tools. as for cheese, i have one of those cheese cutter things that uses piano wire to cut with.
the old sailor
 
i have been cooking professionally for 7 years now. the sharper the knife the longer the cut material lasts. when cutting say spinach, romaine lettuce, or tomatoes (these just being very common) if you use a semi sharp knife you tear the fibers of the vegetable reducing its shelf life.


here is a simple easy test you can do at your home. grab 2 heads of romaine lettuce. use your duller knife to process one head to the cut size you would like. then sharpen your knife and repeat with equal size on the second head. Put them into ziplock bags or containers and pop them in your fridge. check on them once a day and see which takes longer to brown.

but in my line of work, the sharper the knife the longer the product will last.


*i cut on a plastic cutting board and have my knife sharpened every other month with a diamond hone used to maintain in between
 
Carrots arent that good a way to judge sharpness. I,ve seen video of "effortless" cutting of carrots using a 0.02"thick spatula with no edge.
 
depends on what your cutting.

if you're cutting fish for sushi or even doing steaks (be it fish or meat), fine finished to around 6k-8k japanese whetstones

if you're cutting up veg, you'd do fine just having a 1-2k finish. specially with tomatoes and bell peppers, you need an edge that's a bit toothy but will still cut well without tearing. you can even sharpen your knives up to 5k and then "strop" it again on 1k really lightly a few times to get back some of that toothiness you need for cutting tougher skinned stuff.

but do not forget that knife geometry also does affect the perception of sharpeness as well.
 
I am leaning a lot. As always things are always more complicated than they seem. I'll sharpen a few a little more to see how I like it and make sure the One Who Must Be Obeyed knows which ones. ;) I do have to learn to sharpen with water stones though. I've always done it just on the grinder and than the strop.

Thanks for the feedback guys.
 
I like my scary sharp. They should cut effortlessly. I think it depends on if cooking is something you like to do or simply a chore. I love to cook myself and like the process of prepping veggies and the like. Many of the meals I like to cook have a lot of prep work and therefore I enjoy using my knives. If you view cooking as a chore, knives probably don't matter as much.
 
I think it depends on what you're cutting, how much you need to cut, and what level of knife skills you have. Soft materials like fish flesh require a very sharp knife. Slicing celery or mincing garlic doesn't require a ridiculously sharp knife to complete the task, but if you are going to be doing a ton of food prep in a commercial setting then you'll probably want your knife to perform well enough that it stays sharp throughout the process. If you aren't a trained chef or don't have excellent knife skills you aren't going to get the most out of a high end knife because you'll prep materials the wrong way, perhaps with too many cuts or whatever. If you are cooking at home for a few people then you probably don't need extremely high end knives taken to 10k grit or beyond.

I take my Victorinox chefs knife up to 1500 grit and maintain on a Kershaw honing steel. I'm not cutting anywhere near what someone in a commercial setting is cutting, however, and I'm not making sushi or sashimi so I don't have to worry about exact cuts of fish. At 1500 grit and even at 40 degrees inclusive the chefs knife is plenty sharp for home use. Someday I may reprofile to 30 degrees inclusive but it stays sharp enough to cut everything I need to cut for months at a time with a little steeling here and there, so I probably won't bother unless I get really bored.

This forum really gets people overthinking things at times, but that's part of the fun and the hobby. If you're looking for an exact answer on what angle at what grit is most appropriate for specific materials, good luck :) 1500 grit at 40 degrees is plenty for me and I love cooking, but like I said, I'm not having to prepare 50 lbs of mirepoix at a time. More than anything I would imagine the edge angle is more important than the grit. Take a 40 degrees inclusive knife at 1500 grit down to 30 degrees inclusive at 400 grit and see which one seems sharper :)
 
Part, see if you can find a video of someone slicing paper thin slices from half of a tomato sitting on a cutting board........lengthwise from the top with no sawing motion and nothing holding the tomato other than the stiction of the board and wet tomato. THAT is the Holy Grail, I think. ;)
 
i know the guy on that vid you mentioned, his username is saltydog55252 on youtube. he's on other kitchen knife forums that i am on. that guy has the most awesome knives. he has in own restaurant. definitely knows what he's talking about.

here you go, his channel on youtube:

http://www.youtube.com/user/saltydog55252

it's a whole different world with kitchen knives, as most folks here will realize. =D

15 degrees on each side (30 degrees inclusive) is the norm in japanese knives. some even take it further to way insane angles but 30-32 degrees gives you the most versatility in both cutting and edge retention. but with other considerations such as steel hardness, geometry, knife skills, and then the cutting board, your mileage may vary. =D

cutting boards matter, which is why most kitchen knife knuts will go to theboardsmith for their boards.

endgrain is best, but edgegrain is okay. no bamboo(it's not even wood! it's a grass lol), hardwood is the best (maple and cherry is usually the norm, nothing too hard like ironwood). plastic is okay, but never stone or glass. there are boards now that are made with rubber, sani tuff is a pretty good choice for synthetic boards.

and then there's the matter of the kind of knife you're gonna use, the proper knife for every application.

can't exactly do fine cuts like brunoise, julienne, and whatnot on a boning knife. you could but it will be very clumsy.

or cutting sushi with a bread knife. that would be just plain silly.


i'm a culinary arts graduate so i think i know a thing or two. =D
 
I am an obsessive sharpener. I do it to get better at holding my angles consistent through the entire edge on a 270. As a result, I now like to have all my knives stupid sharp, even my work knives keep a very keen edge.
 
I have a habit of steeling up the edges whenever I am preparing a meal where meat or vegetables need cutting up. The edge will shave hair off the arm. There is less bruising and crushing of food, and less effort in cutting by keeping the edges up. Once steeling nolonger can restore the edge I go down to the shop and grind the edges using a 400 grit, then set them with the ceramic rods before returning them to the kitchen.
 
I've gone as low as 10 degrees per side (dps) on kitchen knives that are dedicated cutters. Even at 10 dps, the primary grind will fail before the edge in hard cutting like bone cutting etc. For others I'll sharpen 10 to 15 dps on a belt sander and power strop the burr off with a leather belt on the sander. I've had no complaints with the high sharpness edges. On my personal knives, I go with a 4000 grit waterstone or the Sharpmaker at 12 to 15 dps. Even the knives used for cutting poultry bones dont get damaged at this angle.
 
As sharp as possible. Keep in mind, a professional chef maintains the edge of his knives daily, before each shift. A dull knife is an unsafe knife. I keep mine at the thinnest possible angle I can manage free-hand. I want it to glide through whatever medium I am cutting with no resistance.
 
I like mine sharp but I try not to grind away too much by over sharpening. Alot really depends on what I am doing and which knife I choose. I was peeling a pumpkin and I use a large Santoku in A2, that one I pretty much keep shaving sharp since it will keep a fine edge and not require much touchup. My commercial knifes I let get pretty dull since I dont want to grind them to nothing.
 
A kitchen "knife" should be absolutely razor sharp with about 10 to 12 degrees per side bevel. Make sure you have a soft enough cutting board. The keys to safety are uniformity in the sharpness and profile of your blade combined with using low force/effort for maximum control. A blade that is thick or dull in one section and sharp or thin in another encourages you to apply too much force and then be surprised when you transition to a sharper or thinner region. That is maximally dangerous. A dull or obtuse blade is dangerous when it requires you to use high force for your cutting. For most purposes use a thin sharp kitchen knife and light force. If you are chopping things (something an amateur should minimize doing) use something more like a Chinese cleaver and a slightly more obtuse bevel. For that I would go 15 to 20 degrees per side. The wide heavy blade will twist less than lighter narrower blades. Remember that blade contour can be used to achieve high edge pressure while using limited force. A curved chef's blade and a rocking motion will break thin flexible fibrous material better than dangerous chopping. I was using an ulu to great effect while dicing leeks last night. On the other hand a razor edge on a thick blade can be dangerous when cutting through a thick tough material. I was cutting through a hard butternut squash last night. Regardless of edge sharpness there is a major amount of wedging that occurs as you split something that tough. I used a blade that was only 1/2 inch wide and about 2mm thick and it was difficult to keep my force down to a safe level. Next time I may just chop it with my thinnest Chinese cleaver.
 
I don't do much in my kitchen except push buttons on the microwave. On the few times that I've had to cut something I've noticed that I can chop vegetables with a very dull knife but cutting meat is a different matter and requires much more sharpness. My other observation is that most people would lose all of their fingers very quickly if they had other than dull knives in their kitchen. I wouldn't recommend sharp knives for anyone that isn't very meticulous with their knife handling. My wife will lay the knives in the bottom of the sink and sometimes that means that a sharp edge is point up, then she will put her hands in there to do something and maybe come right down on top of the sharp edge. I've pointed this out to her a few times. A knife enthusiast or trained cook might be more careful with their knives but the average person in the kitchen is not.

It is interesting to see what is recommended for cutting boards. Some people won't use wood cutting boards at all because they harbor bacteria. I hate to think of what a plastic or glass cutting board does to a good blade. I was thinking I might have to sharpen our knives at a large included angle to make the edge resist rolling.
 
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