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Dec 8, 2009 01:44 PM

knife health

I just bought a new knife and I'm so delighted with it. It's light ( carbon stainless) and sharp, so it's fast! I have a knife sharpener, it has two tracks that you pull the blade through. It hasn't seemed to help my old ones much, so I think I will have to get an additional new knife or two or three. Here's my question, regarding the new knife. How often should I sharpen it?


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  1. I am not a knife specialist, but I would stay away from knife sharpener. The proper way to sharpen a knife is on a stone. As for how often you need to sharpen it, well, it depends on how much you use your knives.

    1. Your best bet is learning to use a stone. It's not as hard as it's made out to be (by people who haven't really tried, usually), it's versatile, it's cheap in the long run, and it produces the best edges.

      Or if that sounds horribly unappealing, your next best option may be paying a professional.

      Most home sharpening gizmos don't work very well, just as yours doesn't. Exceptions:

      1. Chef's choice electric sharpeners. These work. Sort of. They just don't work all that well and are expensive to boot.

      2. Belt grinder. Does work. Could also easily destroy a couple dozen knives before you get the hang of it.

      3. Edgepro. Works fantastically well. Less of a learning curve than freehand sharpening. But quite expensive.

      4. Spyderico sharpmaker. Reputed to work, though not as well as stones or an edgepro. I haven't tried it.

      None of those four options work for all types of knives. What type of knife did you get? That might help indicate how it should best be sharpened.

      Edit: I didn't even see the word 'often.' My bad. To answer the question you actually asked - you should sharpen it as often as needed. It depends on the knife, how you use it, and your standards for sharpness. I sharpen my knives long before they get as dull as they would be fresh from a chef's choice sharpening - about once a month. For most, that's overkill. Some sushi chefs sharpen nightly. Other people don't sharpen for years at a time and insist their knives are still sharp, just going to show that "sharp" is subjective.

      27 Replies
      1. re: cowboyardee

        Thanks. What I bought at Sur La Table is a Chef's Choice, multi-edge, purportedly easier than a stone. It has diamond head devices that you manually pull the knife through. It is NOT electric.
        I got an 8 inch Japanese chef knife. It's hollow carbon steel and really light. It has these little grooves so food doesn't stick-- it's amazing-- cut ( no pun intended) my prep time in half! I think its Miu or something like that.

        I also have a long steel thing, that I have been told is for sharpening and I have been told it's only for straightening. I inherited from it from my Dad, and I'm pretty sure he kept his chef knife sharp that way.

        1. re: withabandon


          Your long steel is probably for honing (straightening a roll edge), unless it is made out of ceramic or diamond. In that case, it can sharpen your knives.

          I had a manual Chef Choice sharpener too. It didn't work very well and finally broke down. I think a flat stone is the best in the long run, but I can understand why some people like simple Chef Choice. It works somewhat, just not great. It is better than not doing anything

          1. re: withabandon

            withabandon, among all electric knife sharpeners, undoubtedly the Chef's Choice that you have is the best. There are two comments that follow upon that, however.

            First, the matter of knife sharpening is one that raises the juices of foodies probably more than any other subject. You will get some very vehement comments that all electric knife sharpeners are dross, and that you will ruin your knives with a Chef's Choice. Very vehement. We do not happen to be in the camp of anti-Chef's Choice electric sharpener people, but we are not prepared to say that their arguments are without basis. The very best knife sharpening is done by hand, with stones, and often; if one is not personally adept in hand sharpening with a stone, the costs (and loss of use of the knives) involved in sending the knives out to be sharpened professionally as often as they need to be sharpened is prohibitive.

            The second point is that (with the exception of one model of Chef's Choice), the Chef's Choice sharpeners reshape the edge of your knives to a unique shape that Edgecraft (Chef's Choice) calls Trizor. The Trizor shape is mechanically stronger, and stays sharp longer, than other knife-edge shapes, but the trade-off is that it yields the last iota of ultimate sharpness to other edge profiles. So, right after sharpening, a knife sharpened to a Trizor edge is not as sharp as a knife sharpened to a 20° double bevel as most European knives are sharpened or as sharp as a knife sharpened to a 15° single bevel as many Japanese knives are sharpened; but after a period of use the European-bevel or Japanese-bevel knives will have dulled beyond the amount that the Chef's Choice Trizor edge will have dulled, and at that time the Trizor edge will be the sharper.

          2. re: cowboyardee

            I have to disagree that the Spyderco works less well than a stone. In my experience the opposite is true, especially for someone not experienced in using a stone.

            1. re: taos

              I meant only that it works less well than skillful use of a stone.

              Almost everything works better than the first time you try to use a stone But the payoff for developing that skill is the most versatile and effective method of sharpening.

              1. re: cowboyardee

                That may possibly be true but I think the number of people who both a) can use a stone with skill and b) care to spend the time learning how to do this, is very small.

                In addition, the difference in performance between an edge sharpened even by a skilled user of a stone and an edge sharpened by a skilled user of something like a Spyderco, is probably very small. I'm sure the knife freaks among us will disagree.

                1. re: taos


                  Is that a preemptive strike right there? I was going to write something to disagree with you, but then I don't want to be labeled as a knife FREAK, so I will have to agree with you now. :)

                  Seriously, it really depends what you mean by "can". The faction of people people who at this very moment can sharp a knife on a stone with skill is small, but the percentage of people who has the potential ability to learn to sharpen on a stone is probably >90%. It is easier than cooking or baking or playing World of WarCraft. Whereas you need at least weeks of experience to cook something decent, we can get a hang of knife sharpening in maybe 3 - 5 sessions. I think the one big hurdle in free hand knife sharpening is the ability to hold the knife at a steady angle. Once you can lock your knife in a 15 or 20 angle very steady, then you can sharpen your knife to good reproducible results. Keep in mind that people used to sharpen their knives all the time. There wasn't any electric knife sharpener and knives back then require more frequent sharpening.

                  1. re: taos

                    I meant to write an elaborate reply to this post. But then Chem went and wrote most of what I was going to say.

                    A couple small things to add -
                    Remember that freehand sharpening is essentially just rubbing a piece of metal on a rock. Apologies to anyone with bad arthritis or parkinsonian tremors, but for most of us, learning to sharpen should not be a difficult process. Merely one that requires practice -- less practice than it takes to use a knife well.

                    Also, just as important - remember that I listed the spyderico as an exception to the "sharpeners are junk" line. Though I haven't used it, I don't doubt that it works well - I've heard this from multiple knowledgeable sources.

                    1. re: cowboyardee

                      The reality is most people don't really want to play with their knives all day until they get the perfect mirror-finish and the edge sharp enough to remove the hair from a snake.

                      Most people just want to be able to put a very sharp edge quickly, safely, and efficiently without making the whole thing into some kind of a cult or a fetish. The point of my original post is that if you haven't used something -- and I've used both stones and the Spyderco and so-called "sharpeners" that can destroy a knife, the Spyderco can work as well as a stone -- you really shouldn't discount it.

                      1. re: taos

                        Reread my posts - no one is discounting the spyderco.

                        The reason I can critique it without using it - its limitations are obvious.

                        The fact is it gives you a choice between merely 2 or 3 preset angles, relies on nothing more than a visual trick as its angle guide, and has narrow rods that slow your progress in comparison to a wider abrasive surface. Try grinding out a nasty chip with one. Or sharpening a dull single beveled knife.

                        As I said, it's a better system than most and its worth looking into. But you're just not giving stones the credit they're due. You don't need to be a cultist to see that.

                        What are you even arguing? That the spyderco can produce results as good as a stone, or that most people don't want said good results and should just stick to whatever's easier? Cuz it's easiest to just pay someone else to sharpen for you.

                        1. re: cowboyardee

                          You said, "The fact is it gives you a choice between merely 2 or 3 preset angles."

                          Well, right away you're wrong. There are more pre-set angles than that, for example an angle for scissors, which I have not tried so I won't even pretend to comment on it. But obviously you could also use that on a knife.

                          More importantly, you can also set either of the stones flat in a track and use them just as you would stones.

                          The reason I'm arguing is that I think it's irresponsbie to discount a tool you have obviously have never even seen, much less used.

                          A lot of people come here asking for advice on how to buy or sharpen a knife and they get answers from the knife hobbyists on this board insinuating that unless they buy the latest $200 Japanese knife and sharpen it daily to a mirror razor edge on stone, there's no point in even owning a knife. Or maybe in cooking at all.

                          1. re: taos

                            "Well, right away you're wrong. There are more pre-set angles than that, for example an angle for scissors... "

                            How many are there? Spyderco's site lists 3 total- two for knives (30 and 40 degrees included) and one for scissors (12.5 degrees, presumably not included). If there are others, please list.

                            Despite appearances, I have no interest in arguing for arguing's sake. If you want to discuss upsides and downsides of a sharpening system, I'm game. For example, it's good to know that the spyderco system allows you to lay the rods flat and use them as benchstones. Good info and useful to anyone considering buying one. And regardless of whether I have personally experienced a spyderco, I'm still correct that it uses a 0.5 inch wide abrasive which could not possibly cut as fast as the same abrasive made wider. Also useful to others.

                            I disagree that you must personally use a device before having any input on it. Probably neither of us has used a slapchop, but we both could forsee problems with its design. My experience with sharpening and sharpening devices is fairly extensive. It translates.

                            However, do not put words in my mouth.

                            Quote: "A lot of people... get answers from the knife hobbyists on this board insinuating that unless they buy the latest $200 Japanese knife and sharpen it daily to a mirror razor edge on stone, there's no point in even owning a knife. Or maybe in cooking at all."

                            I have not said this or anything like this here or on any other thread. No one here did.

                            1. re: cowboyardee


                              Since scissor blades are chisel ground, the included angle will be the same as the edge angle. That being said, that 12.5o angle is neither. I believe it produces a 77.5o edge angle (90.0-12.5). Problem is that most commercial scissors have an angle smaller than 77.5o.

                              For your information, this is the "12.5o" scissor edge Spyderco refers to for a different product:


                        2. re: taos


                          Very good points, but I think you may have a very narrow view of flat stone sharpening. It is actually the most common, oldest and dirtiest sharpening methods. If you ever been to back alley of a Chinese meat market, a Japanese fish market, you will see that is the method for knife sharpening. Hunters and campers often sharpen on a little flat stone. Yes, it is true that if you are want extremely smooth and sharp edge on a high quality knife, then you need to resort to high quality flat stones. However, the perception that only those people use flat stones is incorrect. Majority of daily knife sharpening are done on inexpensive flat stones around the world. If anything, if you take out a Spyderco in a village in India or China or anywhere, you will be the one viewed as being really weird.

                          I agree with you that most people want to put a sharp edge quickly and efficiently, but I disagree that flat stone sharpening is cultish while Spyderco is normal. 99.9% of individual sharpening around the world are done on a flat stone and these people are not freaks, do not belong to a cult and do not have a festish.

                          1. re: Chemicalkinetics

                            What I have is NOT electric. It is a manual device with guide channels so you don't accidently ruin the knife. Are you all saying that this will dull my knife instead of sharpening it. If the thing will work to any extent, how often do you recommend sharpening?

                            1. re: withabandon

                              If you took a sharp new factory edge and put it in a roller sharpener, it would dull most knives. If you waited until your knife was quite dull and then used it, it would make the knife sharper.

                              How often to sharpen is a tough question than you think. The only honest answer is 'it depends.' Sharpen it when it feels dull to you as you use it. I'd hazard to guess that most dedicated home cooks sharpen on average, maybe once a year, but I don't really know.

                              It's not just that sharpness is subjective. It's also that knives are different as are users. Someone who uses a forschner to bang through winter squash and turkey bones for an hour a day every night is gonna have a dull knife MUCH sooner than someone using a super hard Japanese knife for a few minutes each weekend to slice sashimi and tomatoes.

                              1. re: withabandon

                                HI withabandon,

                                What I had is also not electric, please see the link, which I posted earlier as well:

                                No, in all practical purposes, it will not dull your knife. It is like sandpaper. Let's say you have a piece of wood and you sand it using a 100 grit sandpaper and then move up to 180 grit and then finish with a 320 grit. You will be smoothing the surface by moving from 100 to 180 and then to 320. However, if you go back and start sanding the surface again using a 180 grit sandpaper, then you are roughing/scratching it.

                                If your knife has already been sharpener by a professional, then sticking it to your ChefChoice can "dull" it. However, in all likelihood, you won't be sticking an already sharp knife into ChefChoice, so hopefully this will never happen. Only a dull knife should be put to a ChefChoice, so it can only be sharpened.

                                You sharp your knife whenever you feel like it is not sharp enough. It is entirely up to what you believe is necessary. It is like shaving. You can shave twice a day, or once a day or once every two days. It is entirely up to what you consider as needed. Some people use their knives a lot and they like shape knife and they will sharpen them once a month or once every two months. Others do not need very sharp knives and only sharpen their once every two years.

                                Please beware that most ChefChoice produces a compound double bevel and its edge face angle is fairly wide. Consequently, it is not suitable for many Japanese knives like Shun, Global.... where the factory angle is already very acute at 15 degree.

                                1. re: withabandon

                                  withabandon, in your original post, you said that your knife ia carbon steel and light; that makes it likely that you have a French-style knife. For ages, the French have preferred relatively soft carbon steel blades, which they sharpen frequently. French chefs are not dumb or naïve: they are well aware of what German and Japanese style knives can do, and yet they have (on the whole) a preference for a knife style that is easy to sharpen, and that takes an excellent edge; for those benefits, they are willing to pay the cost of the knives getting dull fairly quickly in use, and the extra measure of care required of a non-stainless steel, which easily rusts if neglected. and can discolor even when cared for.

                                  The Solingen blades (German) historically have been fabricated from relatively harder steel, often stainless steel, and forged to a heavier gauge than French-style knives (of course, French-style blades and Japanese-style blades are also made in Solingen). Those factors make a "German" knife harder to sharpen than a "French" knife, wherever the blades are made. Contrary to what the newbies who think of only German (which they call soft) and Japanese (which generally, but not universally, are hard) knives have received as conventional wisdom, the relatively soft French carbon steel knives take a wickedly sharp edge, as sharp as any knives in the world -- but they also lose the edge fairly rapidly in use, and thus need to be sharpened more frequently. If you have a French style blade, then you will need to sharpen it more frequently than you would need to sharpen a German style or Japanese style blade.

                                  As we pointed out in our post earlier in this thread, Chef's Choice sharpeners are designed to put a "Trizor" edge on a knife. Depending on one's point of view, that either "dulls" the edge (bad) or makes the pretty sharp edge that the Chef's Choice grinds less susceptible to deformation and thus able to last longer between sharpenings (good).

                                  1. re: Politeness

                                    You're right about french carbon knives. I have a soft spot for old carbon sabatiers and would certainly buy one if I were wealthier- full bolster, soft steel and all. Potential sharpness is not directly related to hardness. This is a hard concept to explain though.

                                    But I believe the OP said he has a carbon stainless (which just means stainless, more or less) Miu knife. I'm not familiar with Miu knives offhand. Glad OP likes it though.
                                    Something like that?

                                    1. re: cowboyardee

                                      If I might suggest that you look at the Sabatier Outlet: . I found this many years ago, in a small South Carolina shop, just off I-95. I have built a good collection over the years and regularly give knives to friends as birthday and Christmas gifts. Excellent pricing and a full range of carbon and stainless knives.

                                      For sharpening, I use a Japanese water stone I purchased from Grizzly Tool. 1000 grit puts an amazing edge on either a carbon or stainless blade and only takes a few minutes.

                                    2. re: Politeness

                                      Thanks to Politeness and cowboyardee for rereading my original post. The knife I have is made in FRANCE. It is a Japanese Style-- or at least that is what it said on the package. I cook a fair amount and use my new knife all the time now. When I brought it home it was razor sharp. Even cut up a butternut squash with it with ease, and prepped everything else i made super fast, Cut prep time by at least half! I don't bring much in the way of physical power to the cutting board being a petite woman. So I was amazed and wanted to keep the knife functioning. Today I noticed that slicing an apple through its skin was not happening easily-- I suppose that means sharpen. Prior to that I sliced off a tiny bit of finger nail effortlessly (obviously that was not my intent) I've never had a knife sharp enough to do that. Anyway, there was slight dulling from the time I first posted till now, so I'm about to sharpen the knife. This knife was not terribly expensive. Under 30 dollars. It seemed to be razor sharp for about a week. So the answer is run it through the sharpener about once a week? Or whenever it seems to loose its sharpness. and not to sharpen it when it doesn't seem less sharp. Is that right. I just need a really simple answer here. I just want the speed it had when I first bought it---

                                      1. re: withabandon

                                        One week is a very short time for the knife that you purchased to dull. Are you using a steel or ceramic rod to hone prior to every use? Regular honing is necessary. Your knife will feel dull very fast without honing. Sharpen when regular honing no longer satisfies. Hope I'm getting it. :)

                                        1. re: rosetown


                                          Is your MIU knife carbon steel or stainless steel? What Japanese style is it? A Santoku? I like to second rosetown. A knife can get dull through different means. The edge of most knife rolls back in time, so it will not cut as well, but the edge metal is still physical there. All you need to do is to straighten the edge back to with a honing steel. In other cases, the edge of the knife gets dull because the edge is chipped off. In that case, you have to sharpen it.

                                          Here is an entertaining video on honing and sharpening. Please watch from time 4:45. It is a pro-Shun video

                                          Strong and hard steel edge (like a ceramic knife) tends to micro-chip before rolling, while soft and tough edge tends to roll more often. For this reason, you never really need to hone a ceramic knife with a steel. Japanese knives usually use harder/stronger steel, so they do not tend to roll as much, while German knives like Henckels and Wusthof requires regular honing.

                                        2. re: withabandon


                                          I've re-read the entire thread and am still thinking about sharpness and my previous reply.

                                          Assuming that you haven't been using the steel inherited from your father, then start using it as a matter of course. It could immediately restore your confidence in the knife. If you're not confident in the handling of the steel many posters can help.
                                          You have also expressed dissatisfaction with your manual Chef Choice sharpener. I assume it has a 20 degree bevel. Using it on a Japanese knife will destroy it's slimer bevel and hence, eliminate one quality you cherish. Since your knife is new, a whet stone, as suggested by many posters, is a good idea. It's very easy to use and it doesn't care about bevels. You adjust accordingly to the bevel of the knife that you are sharpening. With a whetstone it doesn't matter if it's a European knife with a 20 degree bevel or a Japanese knife with a 15 degree bevel.
                                          If you lack confidence some suggest purchasing a cheap knife or a using a knife that you dislike to practice. Remember that many sharpen only once or twice a year.

                                  1. re: scubadoo97

                                    What a great video!! Still laughing. He seemed to understand what he was doing. I have one of those cinder blocks. Dare I?

                                    1. re: scubadoo97

                                      This is exactly my point. A lot of people sharpen their knives on pavement and on concrete block. I watched my neighbors sharpen their knives on cheap stones sitting on pavement when I was a kid. A lot of people still do it. Sure, as we get more resourceful, we start to sharpen on refined stones, but the technique of flat-stone sharpening is exactly the same. It is fast, cheap and raw.


                          2. I get my Santoku sharpened once a year by a professional then touch it up on a sharpening steel almost every time I use it. Rather than getting rid of your old knives I would suggest trying a professional sharpener. Prices for me vary by size of the knife, between $4-$9 or so.