Notes from a professional knife sharpener

Eric E. Weiss is a professional knife sharpener who, unlike most others in his field, does it all by hand. He either tackles the blade freehand or clamps it in a jig that he modified. When he's working, Weiss sharpens around 40 knives a day. The San Francisco Chronicle invited Weiss tell his own story:
I started sharpening knives when I was 5. By the age of 10, I was making money from it. My friends in the Scouts paid me 5 cents to sharpen their knives! But I never thought I would have a knife, scissors and gardening-tool sharpening business when I grew up.... You should definitely be using a sharpening steel - the tool that comes with any knife set - every time you're done with your knife. Hold it straight up and down on your table. Start from the heal or the guard, depending on your knife, and draw it straight down at a 25-degree angle. Two or three times either side is all you need. More than that, you start removing your edge.

Dishwashers are my No. 1 nemesis. People seem to think that any knife can be put in a dishwasher. But in fact it's like sandblasting your car in order to clean it. The knife is banging against the basket, getting chips, nicks, dents, dings. And if the knife has any sort of quality steel to it, the dishwasher can remove the edge in two, three washings.

Some people think dull knives are better than sharp knives because they're safer. Wrong! You're pushing and exerting much more pressure on a dull knife. So when you finally break loose, in most cases, your fingers are in the way.

"Knife sharpener Eric E. Weiss gets to the point"


  1. I want to go study at this learned man’s feet for the next 15 years. I sharpen my own knives but I feel like I’m never getting the blades REALLY sharp.

  2. I need magic knives that can go in the dishwasher and never lose their edge, or a magical knife sharpener that always does it right.

    There is money waiting for the wizard that can give me either of those things.

    My Henkels are haven’t been sharpened in 15 years and I still cut with them. I wonder what sharp knived would be like.

  3. Good post.

    The trick is getting the consistent angle along the entire edge. I like the Spyderco Triangle Sharpmaker, and their Tenacious folding knife at $30 is the best bang for the proverbial ducat I’ve ever seen. Sent a few out as presents.

    For kitchen knives, besides the dishwasher include the sink and the cutlery drawer. If these places are where you might put your knives, you’re better off keeping the edge dull.

    I always thought that the quick treatment you give after every use is “honing,” while “sharpening” or removing steel to rework the edge is done infrequently.

    According to Spyderco, there is such a thing as “utility” sharp versus “scary” sharp. A really sharp knife to someone who is unaware of the recent change can be dangerous.

  4. “Never put knives in the dishwasher” was something that my mother taught me. Her reasoning may have been off, because I don’t think that the dishwasher gets hot enough to affect the temper, but comparing it to sandblasting gives one a good idea of how the fine grit in dishwasher soap works.

  5. I use an EdgePro Apex, and I can easily get “pretty darn sharp” but have a very hard time getting “very sharp” … like many things, I need to spend more time at it (and learning at the knee of someone who knows a lot about it would be nice, but …)

    IMHO, “scary” sharp is so sharp that you wouldn’t notice if you cut yourself badly until you see the blood on the cutting board. You certainly need to be careful with edges this sharp…

  6. I sharpen my own knives too, and my kitchen knives are kept razor sharp at all times.

    This is how I keep my knives sharp and in good condition:

    1 – Use the steel before each use, as the man said in the article, just a couple of passes on each side is enough.

    2 – Always use a cutting board. Always. Don’t use those glass or super hard cutting boards. And *never* use the counter top as a cutting board.

    3 – Hand wash, dry and store your knives immediately after use.

    4 – My knives are either in my hand being used or in their drawer, where they lay flat, side by side. They’re *never*, *ever* left in the sink, on the counter top, in the dishwasher or lumped together with a bunch of other utensils.

    It’s not hard to do, you just get used to this routine. Your knives will thank you.

  7. I bought a cheapo manual diamond sharpener (from Cuisinart) for about $15 that has a coarse and fine side. A few pulls on each side gets most knives VERY sharp. I have a Santuku knife that is made by Farberware or someone… it was OK until I sharpened it and now I can cut tomatoes just by applying pressure down and giving the blade a little push forward.

    One thing to be aware of, of course, is that cheaper decent knives will rust so you can’t just leave them around waiting to be washed. I have some rust spots on this knife because of that.

    Another thing – I always put good knives in the block upside down to avoid dulling the edge.

    1. One way to prevent rust spots is to make sure you wash the knife with soap whenever you cut something that’s acidic like a lemon.

      You can use a cheap plastic dishwasher that is basically a hollow handle to hold liquid soap with a sponge on the end. This will keep your fingers safe.

      My goto knife is the Wüsthof Classic 8″ chef’s knife.

  8. As far as knife safety and effective use is concerned in the kitchen, there are knife skills courses or videos that will show you the correct way to use a sharp knife.

    The trick is to slice consistently sized pieces of lets say a pepper in order that everything cooks at the same rate (and is more pleasing to the eye), then throw away what you can’t match. Also, you risk getting cut by trying to get the very last piece.

    Whenever I hear a Food Network personality say that you need a serrated knife to cut a tomato, I know that they don’t have sharp knives available.

  9. I second the Spyderco Sharpmaker. You can quickly go sharp enough for general use, or a with a little more effort get down to razor sharp. You can also use it to sharpen other things, like scissors and shop tools. Mine also came with an instructional dvd, and I think I got it for about $35.

    Then just steel you knives before use, and another run or two during heavy use. Also, handwashing and drying your knives, and a good wooden cutting board are essential. I keep my chefs knives, santoku, and several other knives on two magnetic knife strips, with my serrated blades all in knife blocks. Still, it’s sometimes good to send your knives out to a professional every now and then. Over time the shoulders of the edge build up and it becomes harder to get really, really sharp. A little more finesse is sometimes needed to get the blade back to where you can adequately sharpen it at home.

    Problem is that now I’ve become the de facto knife sharpener for my entire family… Ugh.

  10. Been wanting to post this. It seems that in DIY circles like boingboing , there tends to be more noise for things that need DIY – in this case knife sharpening. That makes sense b/c a post on serrated knifes would not be as exciting b/c there’s no way to sharpen them ; hence, no DIY experience. B/c of the lack of word, I think most have the misconception that plain straight edge is always superior to serrated knife.

    However , the truth is much more complicated — involving the type of steel (how well it holds an edge) , thickness of the knife (type of angle you can sharpen and hold), hardness/softness of object to be cut (how often you’ll need to sharpen), quality of the cut required (sashimi , julienne basil).

    I think unless people like to sharpen knifes for fun ,or have a special requirement on quality of slice/cut , or have to sharpen on regularly due to excessive use (e.g. restaurant), a serrated knife is most often an underrated alternative.

    I love to hear other’s opinion.

  11. Rules for visitors to my house
    1) Do not touch my knives.
    2) Re-read rule #1.

    If I had a dollar for every guest that has grabbed my carbon steel 10″ sabatier and proceeded to cut a pie in a pyrex pie pan cut a steak in a cast iron skillet? Oh man, I’d have enough money to buy new friends. Anymore I just keep a couple crappy Chicago Cutlery beaters lying around for people to abuse, and remind guests not to touch the pretty knives.

  12. I’ll toss in my vote for the Spyderco Sharpmaker, too. I use it for most of my knives, and it works great. For my Japanese knives, which have a very high-carbon-steel forge-welded between two softer pieces of steel, the Spyderco is a bit much (though I sometimes touch them up with its extra-fine rods), at which point I pull out the waterstones and spend some quality time with them. Getting good at sharpening takes time (that’s what I tell myself, since I’m not quite there yet), but really sharp knives are enormously satisfying to cook with.

  13. A friend of mine used a really, really nice knife I got as a gift to hack at a pig carcase. I wanted to kill him. Luckily we have a really great knife sharpener in Austin, but even he couldn’t fix it. I sharpen my own and then just take them occasionally for a pro job.

  14. Here’s a guy that appreciates sharp tools:

    woodworking section starts around 4:00. The entire film ‘Alone in the Wilderness’ is really fun to watch.

  15. As many have pointed out, there is much wisdom on sharpening on the intertubes. However, there is also a lot of bad, and even outright wrong information. I own a fair number of decent blades, and made about a dozen in the last 5 years. I’ve been sharpening anything I could for over 20 years. The rules I tell people who ask: (1) In general, most consumer-oriented stainless steel blades are not good steel. A quality, high-carbon steel will hold a much better edge, longer. Yes they will also rust quicker. Your average home cook won’t go through the hassle of drying a HCS blade every cut, so get quality stainless. MAC knives or Global…good steel at reasonable cost. (2) What is sharp? Depending on what you are cutting, you may want a bit of “tooth” on the blade. That razor sharp sushi knife may work great on fish, but won’t cut a tomato or pepper. That’s why serrated edges are often handy. (3) Sharpening steel: They don’t sharpen. They dress the edge by straightening deformities. Used incorrectly they will ruin a good knife. They will also wear down a good knife surprisingly fast. Practice on cheap blades first. I prefer a ceramic hone over a steel. (4) Sharpening angle is very important to keep constant…otherwise you will just round over the edge. Buy a jig. Lansky is cheap and good. (5) Waterstones are fantastic, but high-maintenance. I find that wet/dry 1000 and 2000 grit silicon carbide sandpaper (bond to a hard, flat, stick) is cheap and does an excellent job. You need to sharpen when it is wet. Dry sharpening will clog your abrasive with swarf…don’t do that! The CMT diamond “stones” are also very good. (6) Practice. (7) Buy a quality wood or wood composite (Epicurean) cutting board and use that. Or, go to a restaurant/food service supply house and get a 12×30″ chunk of white UHMW plastic (like you see at deli counters) and use that. Clean with bleach solution, rinse and dry. Hard plastic, ceramic, granite, etc cutting boards are not suitable. If it’s harder than your blade, your blade will lose.
    (9) Cut a lot of tomatoes? Ceramic blades are fantastic, if a bit delicate. You can’t sharpen them, but boy do they cut!
    (10) Don’t wait until your blade is dull. Hone it every few days, and you may never need to actually create a whole new edge from scratch.

  16. I’ve been sharpening my knives recently on Japanese waterstones, and it’s really fun. It’s crazy relaxing to sit for 20-30 minutes doing nothing but sharpening a really good knife on progressively finer stones — the last feels like marble, and you have no idea how it could sharpen anything. The relaxation effect could easily be because of my mental associations with Japanese knife sharpening and zen, but it doesn’t make it less real.

    That said, I don’t often have time to spend 30 minutes on a single knife — even though the whole point of such a meditative exercise is to make time for it and carve a slice out of your hectic day — so each knife probably goes a month or two between sharpening. That said, I get them amazingly sharp, and so they may not need too much more.

    One other good tip for knives, in addition to those said above, is to store them in a block or a magnet. I have a great knife magnet above my chopping block, and so they don’t hit each other as they would in a drawer.

    @Anon #12: I would hate to use a serrated knife for almost anything I chop. Using a sharp flat chef’s knife I can chop onions finely and quickly using a simple push down and a slight forward motion. To cut with a serrated knife you need to saw at your food, or at least use a long continuous forward motion. A flat blade simply parts the food as it travels downwards, unlike a serrated blade which rips the food apart. With a serrated blade, I would be much slower, and it would be impossible to get the thin, even, smooth slices you get with a flat blade.

  17. Over the summer, I inherited an ages-old whetstone from my father-in-law (he was moving into a convalescent care center, and no longer had a need for the stone) What an amazing difference it made to my far-from-high-end kitchen knives!

  18. Lovin’ all this knife geekiness.

    1. I try to use as few knives as I can in the kitchen. That’s why if I can get through a mise en place with just my chef’s knife, I’m happy. I might have to resort to a deboning knife or a paring knife, but I’d rather not.

    Plus, you can only get the feel for a knife by using it as much as you can. If you’re doing veggies a lot, you can get by with just a good santoku.

    2. Knife sharpening is an art and has nuances I’ve yet to discover. Mr. Weiss is a treasure. “Swarf” is new to me, and “lurch” I appreciate your post along with the other diehard knife enthusiasts.

    3. The whole point, and I think this was alluded to already, is that it’s not about seeing how sharp you can get your knife, but how you can make the experience of breaking down onions, celery and peppers so delightful that you’re cooking more with fresh ingredients. The average supermarket throws away 30% of their produce. I would guess that the average shopper throws away a higher percentage of the stuff sitting in their frig because they think it’s too much of a chore to wash and chop up the stuff.

  19. I always use a steel after use. It does most of what is needed. You can feel with the regular steel when you’re getting an edge; the blade just drags a little more as the tiny burr gets folded back and forth. You can also feel the direction of the burr with your fingertips, and it swaps sides as you dress each side of the blade. A few light strokes and you’re done.

    Sometimes it isn’t enough though; I just also bought a diamond steel that takes it to another level in terms of the amount of material it can remove. I use that one VERY sparingly, only when I can’t seem to get an edge with the regular steel. I then follow up with the regular steel and presto, a great edge.

    I have this fantasy that someday I will befriend one of those celebrity chefs who will come to my place, and when helping prepare dinner, will compliment me on the sharpness of my knives.

    (No dishwasher, my knives never touch any other metal and are stored in a wooden block. I’m borderline OCD on this stuff)

  20. I’m a knifemaker. I’m only an amateur, but I’ve been doing this for some 20+ years, and have made hundreds of knives.

    The best advice I can give you is to keep your good knives out of the dishwasher. The harsh chemicals and physical abuse will, quite quickly, remove the sharp edge and damage the rest of the knife.

    The number one complaint I hear from customers is that the knife they bought or were given discolored or lost its edge in the dishwasher. I include a “care and feeding” document with each knife, which includes a “no dishwashers” statement, but which is routinely ignored.

    I did a survey once of my customers, asking them what they wanted most out of a knife. Over 90% said they wanted something they could just throw in the dishwasher.

    It makes this one bladesmith sad.

  21. Read this in the Chronicle this morning and said (a) God I hate this paper, then (b) cool and (c) I remember way back before Julian Assange BB always ran stuff like this.
    You are a wonderful site.

  22. I inherited one of those grinding wheels that you ride like a bicycle. I gave it to a friend so that I wouldn’t have to ship it cross-country.

  23. FYI that jig and stone set he’s pictured with is a Lanksky Sharpening System (available on Amazon and elsewhere). I’ve used those for 20 years or so to sharpen my knives. They hold the stone at a specific angle (with multiple angle slots for various types of knives). They’re the best general purpose sharpening system I’ve seen.

  24. Eric has a booth at our local farmers market. He’s done a great job with one of my old Wusthof serrated knives and also a Cuisinart blade which dates back to the mid 80s.

    1. Watch out for the guy at the Oakland farmer’s markets. I had wanted to take my nice Japanese knife to a pro, so I brought it to him and asked if he knew how to sharpen it. Upon his word that he did, I gave it to him.

      The guy used a belt sander :( I didn’t realize until I got back.

  25. I put my knives in the dishwasher. Want to know why? Because it’s 2010. If you want to wash crap by hand, go buy a time machine and visit any era before 1950 AD.

    1. I don’t ever put anything in the dishwasher because I prefer not to have my dishes, glasses and silverware all look frosted after a year. And because washing my dishes in the sink guarantees that I’ll get a good handwashing at least a couple of times per day. In related news, I hang my clothes on the line to dry because they last several times longer than if they went in the dryer.

  26. Eric Weiss “sharpened” my knives once. I went to his booth at the farmers market. I guess I figured because he looked so, I don’t know, authentic(?) that he must know what he’s doing. I’ve also seen lots of activity at his booth, which I took as tacit recommendation. He might have gotten my knives a little bit sharper, but my Spyderco does a much better job. Just sayin’.


    I’m amazed no one here has commented on Blade magazine.

    If you really want to learn about knives, and sharpening,
    pick up an issue of Blade magazine. You’ll learn a ton.
    It’s one of the few magazines I’ve ever read that spends
    half of each educating the reader on materials and technique.
    Metallurgy, and nearly every issue has multiple sharpener
    reviews. I am not affiliated with them at all, I just love
    the magazine a ton, and no one here seems to know it. If
    you want to learn how to sharpen, what to use to sharpen,
    and all that goes into different blade steels, perfect edges,
    and all that, get one.

    You CAN sharpen serrated blades! They make special round files
    or ceramic rods for this task. Do not go out and buy chainsaw
    sharpening files for this!

    Lastly, on Japanese whetstones- yes, they put a crazy edge on.
    But they are normally only used for kitchen style knives, mainly
    also for professional fish monger knives. The giant, spear like
    blades used in places like Tsukiji fish market. Previously used
    and still used on Japanese swords as well.

    They are overkill on normal pocket knives, which are mostly used
    not for fine slicing, but general utility use. A razor-blade or
    scalpel edge is possible on them, but you are wasting you time
    unless you use your pocket knife to do surgery. You will simply
    dull the edge faster, and each time, remove more metal from the blade
    than you need.

    Ceramic rod systems like the Lansky are what most people use if they
    sharpen pocket knives, and from what I hear, work just as well on
    kitchen knives. Don’t oversharpen your knife if you won’t need to,
    you’re just wasting the steel you remove.

  28. I’m a professional knife labourer. I’ve worked as a butcher, skinner, field harvest worker and with fish and seashells.

    His advice is not bad, but it is lacking somewhat.

    First of all. Most people only need a serrated knife and some good scissors in their kitchen. A couple of small peeling knifes may be of good use too (they cost about 5 SEK, where I live). Anything more fancy then that is usually overkill.

    The most persistent myth about knifes are that the harder the steel, the better. WRONG! It was true 300 years ago (in Sweden, I don’t know anything about the historical skill of any other countries metallurgists). Even the knifes with the softest steel you can buy today, have harder steel then any knife you could get then. The fancy, very expensive, hard steel (or ceramic) knifes that are sold today are brittle and loose their edge really fast. Knifes with a softer edge last at least 40 times longer, before need of any destructive sharpening. The sharpest you can get a hard steel knife is like a razor-blade or a scalpel, I could never work with a knife that dull, my health would be destroyed within a week.

    If you want to do your life complicated and don’t want to use a serrated knife. Look what factory workers in the food industry use, restaurant workers are amateurs when it comes to using knifes in comparison. I’ve probably used more then 100 different brands of knifes. I’m a huge fan of Frost’s knifes for industrial use (they cost about 10-80 SEK, depending on size), but their knifes marketed to restaurants and homes really sucks. Fiskar’s have some really good knifes, just avoid their expensive ones, they are not as good. IKEA have had some nice knifes and some really horrible. I’ve used 20 or so US brands of knifes, but none of them were any good, they couldn’t get sharp enough and were to brittle.

    When you buy a knife for slicing, avoid knuckle busters.

    Then you need a packer steel with a magnetic core for sharpening the knife. The smooth packer steel is the big secret in how to keep your knifes sharper then a razor-blade and the reason soft steel knifes has much longer life span then hard steel knifes. Always use this steel before you use your knife. Unlike a butcher’s steel, it will not shorten the life span of your life, it will prolong it. It doesn’t remove any material from the knife, it just straightens microscopic bends on the edge.

    After a few years (about 4 months if you use the knife 40 hours a week), or if you have a hard steel knife, you will need a butchers steel. I find that most of these are a bit to aggressive and try to find those that are made in a rather soft steel with very little teeth. Ceramic ones can however replace a grinding stone, in the hands of a skilled sharpener (it took me a year to master).

    As for actual grinding. If you take care of your knife and only use it in your home kitchen, you will not have to do this for decades. I prefer two kinds of rubber grinding wheels at high speed (with lots of water for cooling), one that don’t contain any hard particles and one that does (but very fine). I first use the one with a bite to form the edge, then the soft one for removing grades and then finish of with a packing steel. It take me about 3-5 minutes to sharpen a knife. Some days I have sharpened about 200-300 knifes (with assistance of someone with a packing steel), all sharper then a razor blade. Knifes sharpened with traditional sharping stones is much better if you need to cut into wood, paper, bone, marrow or something with mineral dust or sand on it, but it takes at least half an hour to sharpen a knife with them. If you use grinding stones, you sharpen the edge with very slow(!) movement against it. If you use a high speed rubber grinder, you sharpen with the movement in the direction of the edge. Always with the edge away from your body, especially with high speed grinders. Always use plenty of coolant (water is better then oil with most modern grinding material). Always use glasses for protection.

    As for how to form the edges. I could write several book on the advantages of different angles and forms. The main rule is: a very sharp angle give a very sharp knife that is very sensitive to wear, less sharp angles gives less sharp knifes, but they are sturdier. You can get a good compromise by a two level edge, this gives an edge as sturdy as what you get with traditional really slow grinding, but is easier to use with a sharpening steel. As I live by my knifes, I use rather complicated edge forms depending on purpose, unless you don’t spend most of your time awake with a knife in your hand, you really don’t have to (e.g. if I will butch several hundreds of animal bodies and have to cut both through joints and meat, then I prepare a knife that have the edge sharpened for cutting through the joints near the shaft and the edge for cutting in meat in the top).

    Never, ever use a knife to cut through bones or marrow, it will kill it. Use a saw or, on birds, a scissor. My opinion is that unless you saw bones for marrows (to bake and use as spread on bread, yummy), you commit a culinary sin when you butch an animal so that you have to cut through bones or marrow, but some of my employers don’t share my view.

    If you have to cut dusty vegetables, always use a serrated knife or scissors. There exist good and cheap throw-away skinners knifes if you have to skin dusty pelts. For thin skins you can also use those cutters that are used for seatbelts (you should already have one handy in your car in case of an accident) or to open cardboard boxes, they can be better then a “real” skinners knife.

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