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View Full Version : How sharp do kitchen knives need to be?



Dave Cav
12-29-2016, 12:00 AM
Regular kitchen knives, not sushi knives sharp enough to do cataract surgery....

Our knives are conventional stainless steel, Marks made in Brazil. I believe they are downmarket Henckels. At first I thought I needed to sharpen them to about 4000 or so grit with my Shapton stones, but this was time consuming and, I believe, ultimately pointless. I eventually bought a medium Spyderco just for the kitchen, which seems ok, but is slow. Lately I have been using an old blue DMT medium diamond "stone", which seems to work just fine and is very quick. Then if I feel the need, a little on the Spyderco.

paul cottingham
12-29-2016, 1:05 AM
Sharp. Shaving sharp, but with some "tooth." The tooth helps for cutting things like tomatoes.

Jim Koepke
12-29-2016, 1:47 AM
If a knife can cut a ripe tomato without crushing it, then the knife is sharp enough. A knife should never slip on a surface into which it should be cutting. The propensity of a dull knife to slip before piercing is what makes a dull knife more dangerous than a sharp knife. The second part of a dull knife is having to use more force to cut.

My kitchen knives get taken to the shop once or twice a year. In the kitchen there is a DMT extra fine stone that is used to keep the knives going between trips to the shop. The DMT stone was epoxied to a block of wood to make it easier (& safer) to use. In the shop they either get sharpened up to 8000 on water stones or up to a translucent Arkansas or a jasper hone on oilstones. Either way they may also get stropped in the shop.

All of our cutting boards are wood, but they can still dull a knife if it hits the surface too hard or the knife's edge is used to scrape things off of the board.

As always, 350320

jtk

Derek Cohen
12-29-2016, 7:36 AM
Everyday kitchen knives do not need to resemble bench chisels. I would argue that 1000 grit is more than sufficient. A slightly serrated edge is preferred to a smooth edge.

My wife destroys the knives - mostly Sabatier - by cutting and chopping on granite. She is a damn good cook, but has no interest in the tools, and would comfortably work with dull knives. I pick up - sharpen - behind her, so I needed a quick but effective method of getting the knives working sharp.

I have used many methods. This is what I currently use ...

http://www.leevalley.com/US/images/item/Woodworking/Sharpening/09A0330i2.jpg

It's the "universal sharpener" from Lee Valley: http://www.leevalley.com/US/wood/page.aspx?p=66738&cat=1,43072

Basically, it's a carbide scraper. A few strokes, and the knife is ready.

Regards from Perth

Derek

Jebediah Eckert
12-29-2016, 7:51 AM
Thanks Derek, I was curious when I saw that. I'm going to give it a try.

Good tip about "if it can slice a tomato without crushing it then it is sharp enough." That is how I treat kitchen knives, but I don't think that's as sharp as a chisel or plane blade. I have the Spyderco Sharp Maker I keep in the kitchen. It should be called the "sharp maintainer" because it excels at touch ups, but slow for the initial sharpening to get the cutting angle where it needs to be.

george wilson
12-29-2016, 9:24 AM
Derek,I have found Sabatier knives to be WAYYYY too soft a steel.

Our favorite kitchen knives are the ones I have made from power hacksaw blades,which are an entirely different saw from the usual ones you can find in the hardware store. I only use the SOLID HSS blades,not the ones with the teeth ONLY made from HSS,and welded onto a softer steel so they can't shatter.

My bread knife hasn't needed to be sharpened in over 20 years. Still cuts like nothing else out there.

Since my wife is a craftsman/artist I trained myself,she knows how to take care on knife edges,not clacking them on plates,etc..

Beyond the set of HSS knives,our favorite s a 6" blade Japanese knife I bought many years ago from LV for about $30.00. A wonderful little knife. It has a paper thin layer of very high carbon steel sandwiched between outer layers of stainless. The whole blade is only 1/16" thick. ALL I now do to sharpen it is hone it quickly on an Atoma diamond stone I bought used from a member here years ago. It leaves a coarse,very toothed edge that will cut a tomato as thin as you can handle the knife( But,WHO wants tomatos that thin?:)) That's all I do. I'm careful to not waste steel as the diamonds are aggressive on steel that thin.

I used to hone the Japanese knife razor sharp,but it was a waste of time . The edge from the diamond stone does the job just as effectively as a smooth,very sharp edge,and only takes several seconds to produce.

Brian Holcombe
12-29-2016, 9:32 AM
1000 grit is fine. I've sharpened knives for people in my neighborhood and generally stop at 1k. That results in an edge sharper then many of them have ever experienced. As a woodworker that seems like only a good start at a real edge but it's plenty for kitchen knives....of the stainless everyday variety.

I have a sushi knife that I keep sharp enough to cut a hanging hair. I can basically strop to maintain.....until one of these same ladies uses it for even one slice!!! Then I need to return to the stones. Many people do not grasp the idea that you can stop cutting once the knife cuts the fish, no need to work it back and forth.

george wilson
12-29-2016, 9:40 AM
Keith: Thank you for editing out the fouled up double post for me. I don't know how that happened.

Prashun Patel
12-29-2016, 9:44 AM
I bought one of these thinking it would be a throw-away. I am amazed that it still works extremely well. My go-to knife has a Hock O1 steel blade, though.

KitchenIQ 50009 Edge Grip 2 stage sharpener. $6.00

Has lasted over a year so far.

Robert LaPlaca
12-29-2016, 10:43 AM
I would agree with the sharp but with tooth camp. SWMBO and I have Wusthof Classic knives, I know knives live a hard life, but maybe it's just me, some of the knives (all Wusthof) seem to hold an edge a whole lot longer than others.

glenn bradley
12-29-2016, 10:50 AM
If a knife can cut a ripe tomato without crushing it, then the knife is sharp enough.

This is what I shoot for. Basically if I take a knife to something and it doesn't slice right into it with just the motion of the knife, I touch it up. Once you have a good edge, routine use of a sharpening steel (I have been using one similar to this (https://www.sharpeningsupplies.com/EdgeCrafter-Oval-Shaped-Diamond-Sharpening-Steel-416-P141.aspx) for over a decade so, a little non-traditional) will keep you going for a long, long time between trips to the shop.

Malcolm Schweizer
12-29-2016, 11:41 AM
I sharpen knives for professional chefs at very high-end restaurants. I use a Tormek to set the bevel (You'd be amazed at how poorly these pro chefs treat their knives) and then use waterstones to take them to 5k and for the higher end knives for chefs that don't abuse their knives I go to 10k, but that's admittedly overkill. Some chefs give me single bevel Japanese knives that require special care in sharpening and those are all done by hand on waterstones to 10k.

My personal knives used to go to 10k but now I typically stop at 5k on the Chosera. My sailing knives always go to 10k for important tasks like cutting multi-braid or cutting limes for my drink.

I use Choseras or Shapton Glass. If using Norton, I recommend going to 8k. Their 4K doesn't break down much in the slurry and I feel needs a finer finishing stone. Choseras are fine to stop at 5k.

Jim Koepke
12-29-2016, 11:59 AM
One thing to remember, always let your spouse know when you have sharpened the knives. DAMHIKT!


I sharpen knives for professional chefs at very high-end restaurants.

Malcolm, this has piqued my curiosity as to how you determine how much to charge. I am thinking of sharpening knives at the local farmers market.

jtk

Jim Ritter
12-29-2016, 12:51 PM
Jim, we have a local service that goes to the farmers markets with a small trailer all set up. They charge $1.75/ inch for knives, $8 for scissors. If it's ok here is the link to their website http://www.sharphamptons.com/pricing-and-services
i have no relation to them
Jim

Sam Murdoch
12-29-2016, 12:51 PM
Has been mentioned up above but to emphasize - You can keep a kitchen knife sharp much longer if you use the spine rather than the edge to
slide things off the cutting board. Amazing how often I see folks using a sharp edge as a scraper :eek:.

As for the question - the tomato test works for me too. More than that and I worry about unwary or blithe knife users bleeding on my counter top and in my food. :)

george wilson
12-29-2016, 1:08 PM
As rough and toothy as I leave the edge on our Japanese kitchen knife,my wife managed to slice 1/16" off the end of one of her fingers! It's hard to deal with the injury when she is dancing a fandango while holding the finger under the faucet! She said it was a "coping mechanism" ! Well,it filled in quite well when it was healed.

I used to sharpen the nose chisels,iris scissors and other surgical items for a plastic surgeon. You actually want a little tooth on some of their cutting tools.

Dave Cav
12-29-2016, 1:30 PM
Thanks. I thought this would be a popular thread.

paul cottingham
12-29-2016, 2:01 PM
Everyday kitchen knives do not need to resemble bench chisels. I would argue that 1000 grit is more than sufficient. A slightly serrated edge is preferred to a smooth edge.

My wife destroys the knives - mostly Sabatier - by cutting and chopping on granite. She is a damn good cook, but has no interest in the tools, and would comfortably work with dull knives. I pick up - sharpen - behind her, so I needed a quick but effective method of getting the knives working sharp.

I have used many methods. This is what I currently use ...

http://www.leevalley.com/US/images/item/Woodworking/Sharpening/09A0330i2.jpg

It's the "universal sharpener" from Lee Valley: http://www.leevalley.com/US/wood/page.aspx?p=66738&cat=1,43072

Basically, it's a carbide scraper. A few strokes, and the knife is ready.

Regards from Perth

Derek

Going to try one of those. Like I said in my comment above, I like leaving a little "tooth" (that's what Leonard Lee calls it, it's really just the edge not quite polished) cause it makes it cut things like tomatoes much better, as it goes through the skin easier.

Jim Koepke
12-29-2016, 2:27 PM
Jim, we have a local service that goes to the farmers markets with a small trailer all set up. They charge $1.75/ inch for knives, $8 for scissors. If it's ok here is the link to their website http://www.sharphamptons.com/pricing-and-services
i have no relation to them
Jim

Thanks Jim, it looks like New York prices are a bit higher than Pacific Northwest prices. I found a storefront sharpening service in Portland that sharpens knives for 60-75¢ an inch.

It will likely come down to what the market will bear.

jtk

bridger berdel
12-29-2016, 4:35 PM
a sharpening steel was invented for just this purpose, and it works very well.





Regular kitchen knives, not sushi knives sharp enough to do cataract surgery....

Our knives are conventional stainless steel, Marks made in Brazil. I believe they are downmarket Henckels. At first I thought I needed to sharpen them to about 4000 or so grit with my Shapton stones, but this was time consuming and, I believe, ultimately pointless. I eventually bought a medium Spyderco just for the kitchen, which seems ok, but is slow. Lately I have been using an old blue DMT medium diamond "stone", which seems to work just fine and is very quick. Then if I feel the need, a little on the Spyderco.

Shawn Pixley
12-29-2016, 5:30 PM
I sharpen knives for professional chefs at very high-end restaurants. I use a Tormek to set the bevel (You'd be amazed at how poorly these pro chefs treat their knives) and then use waterstones to take them to 5k and for the higher end knives for chefs that don't abuse their knives I go to 10k, but that's admittedly overkill. Some chefs give me single bevel Japanese knives that require special care in sharpening and those are all done by hand on waterstones to 10k.

My personal knives used to go to 10k but now I typically stop at 5k on the Chosera. My sailing knives always go to 10k for important tasks like cutting multi-braid or cutting limes for my drink.

I use Choseras or Shapton Glass. If using Norton, I recommend going to 8k. Their 4K doesn't break down much in the slurry and I feel needs a finer finishing stone. Choseras are fine to stop at 5k.

Like Malcolm, I sharpen to 12,000 grit. The knives are steeled with each use. Three knives get sharpened more than others - chef's knife, paring or petty knife and boning knife. I sharpen when needed (~3 months). I really hate dull knives.

My pocket knife (Kershaw one hand opener for boating & fishing) sees the most abuse and difficult cuts. Its shape makes it more difficult to get really sharp.

James Pallas
12-29-2016, 6:36 PM
My unscientific research has convinced me that most people use dull kitchen knives. I concluded that it is not always a good idea to give such persons a sharp knife so I keep them separated. If you give someone an inexpensive ceramic knife they will be thoroughly impressed. I go to 3000 because that is what I have in the kitchen at present, old water stone. I would guess that 1000 would be fine in most cases.
Jim

Malcolm Schweizer
12-29-2016, 7:08 PM
One thing to remember, always let your spouse know when you have sharpened the knives. DAMHIKT!



Malcolm, this has piqued my curiosity as to how you determine how much to charge. I am thinking of sharpening knives at the local farmers market.

jtk

After researching, and seeing everyone charging per inch, I decided to make it easy- $5 a blade, $4 for regulars or if you give me a lot to do at once. It evens it out. I do charge more for machetes based on length. I started it just to pay for the tormek. It paid for itself in a month or two. I now just sharpen for top restaurants because I got tired of repairing blades for chefs that abused their knives. Whenever I retire, that will be my supplement. I can easily make $250 in a week just doing a few restaurants.

steven c newman
12-29-2016, 7:31 PM
One other caution to be observed....when you do sharpen the Kitchen knives up..TELL everyone you did just that. Otherwise, someone used to that old, dull beater...might just find out how sharp is SHARP!

Jim Koepke
12-29-2016, 9:37 PM
One other caution to be observed....when you do sharpen the Kitchen knives up..TELL everyone you did just that. Otherwise, someone used to that old, dull beater...might just find out how sharp is SHARP!

Someone mentioned to me that maybe a box of Band Aides should be kept next to my sharpening set up. If anyone asks just say, "those are for the folks that don't believe the knives are actually sharp and have to see for themselves."

jtk

Mike Henderson
12-29-2016, 11:53 PM
I have a power honer and when I'm going to cut meat, I hone the knife to the point where I could shave with it. For many other applications, I have a ceramic sharpener that I use to get a decent edge.

And just a note on "steeling". Don't steel sharp knives. Knives have traditionally be made with a relatively soft steel and the edge failed by rolling over. The steel pushes the rolled over edge back to straight. There's a limit to how many times you can do that and that's when you have to sharpen.

There are knives made now that have a very hard center - laminated Japanese knives, for example. Steeling won't work on those. They fail by chipping and not by the edge rolling. There's a western knife that has a very hard center - see here (https://www.liquidiamondknives.com/). I have one and it holds an edge for a long time. When the edge fails, it does so by chipping. To sharpen it, I use a diamond stone to wear the edge back past the chips (they're small) and then I power hone the edge. The advantage of the knife is that it sharpens to a VERY sharp edge and holds it for quite a while.

Mike

[Steeling a knife does not remove any metal from the knife - it just straightens the edge - so it won't "sharpen" a knife.]

Jim Koepke
12-30-2016, 1:42 AM
I have a power honer and when I'm going to cut meat, I hone the knife to the point where I could shave with it.

That's what it takes to make paper thin cuts from a piece of leftover prime rib for a sandwich, yummmmmm!

Bet you can guess what we had for Christmas dinner.

jtk

bridger berdel
12-30-2016, 8:59 AM
Most foodstuffs can be fairly described as bundles of wet fibers saturated with lipids and sugars. They cut well with edges that are reasonably sharp and very finely serrated.

There are outlier cases, things like tomatoes where the skin is thin, smooth and tough over a soft interior, carrots where the fibers are brittle and tightly bound or bone which must be processed but is too tough to itself be eaten. These will have different edge requirements.

Knife sharpening steels come in a range of smoothnesses ranging from being basically a polished rod to being basically a linear file, with a corresponding range of balance between burnishing action and cutting action. A polished steel will produce an edge that will shave, if not comfortably but requires an edge that is pretty sharp to start with. A toothier steel will work on a knife in worse shape and produce an edge with more "serration", removing more metal from the knife (detectable by wiping both down after with a white cloth.) I prefer a fairly smooth but not polished steel for typical stainless steel kitchen knives.

Shawn Pixley
12-30-2016, 8:11 PM
Someone mentioned to me that maybe a box of Band Aides should be kept next to my sharpening set up. If anyone asks just say, "those are for the folks that don't believe the knives are actually sharp and have to see for themselves."

jtk

When I sharpen my plane blades and chisels, I test sharpness by shaving my forearm. I never cut myself. But last time I sharpened the knives (last weekend or so), I cut myself. Smallest of cuts (the knife was sharp) but I bled and bled. Band Aids are kept whereever LOML or I can cut ourselves (shop, jewelry studio, kitchen, etc.).

LOML cut the tip of her finger on a sharp chef's knife (poor off hand technique) the other day.

Hilton Ralphs
01-01-2017, 5:34 AM
I bought one of those hand held 12 inch honing steel rods. I then showed my wife how to hone each side of a knife a couple of times before or after use and now the knives never get to the point where I need to use a grinder in anger.