Discuss Cooking - Cooking Forums

Discuss Cooking - Cooking Forums (http://www.discusscooking.com/forums/)
-   Knives (http://www.discusscooking.com/forums/f90/)
-   -   How sharp is "sharp"? (http://www.discusscooking.com/forums/f90/how-sharp-is-sharp-56068.html)

AlanS2323 03-10-2009 06:25 PM

How sharp is "sharp"?
 
So here's the thing...I have a cheap set of knives that I sharpen several times a week. I'm obsessive about them being sharp, but others have told me I'm being ridiculous and there's no need for a knife to be sharpened that often.

What I would like to know is what is a reasonable sharpness? Is there some kind of test that's recognized to mean a knife is really, really sharp? For me it's the tomatoes and bell peppers that get to me. If I have to apply pressure and really start sawing, I think the knives aren't sharp enough. Unfortunately, I've never gotten to that point with my knives...so I'm wondering if I just have impossible standards or whether my knives are substandard.

Uncle Bob 03-10-2009 06:31 PM

Welcome to DC ---- Your "tomato" test seems like a reasonable standard ---

Have Fun & Enjoy!!

Andy M. 03-10-2009 06:43 PM

It's not wrong or unreasonable to want sharp knives.

What's scary is that you have to sharpen your knives several times a week!

If you are referring to using a steel on the knife, that's not sharpening. I use a steel every time I use my knives. That's basic maintenance. If you're using some sharpening stone or tool that often, you need new knives.

I have a set of Henckels PRO S and sharpen them a couple of times a year. Any of my knives will easily cut through a tomato or bell pepper at any time.

jpaulg 03-10-2009 07:42 PM

Quote:

Originally Posted by AlanS2323 (Post 801400)
So here's the thing...I have a cheap set of knives that I sharpen several times a week. I'm obsessive about them being sharp, but others have told me I'm being ridiculous and there's no need for a knife to be sharpened that often.

What I would like to know is what is a reasonable sharpness? Is there some kind of test that's recognized to mean a knife is really, really sharp? For me it's the tomatoes and bell peppers that get to me. If I have to apply pressure and really start sawing, I think the knives aren't sharp enough. Unfortunately, I've never gotten to that point with my knives...so I'm wondering if I just have impossible standards or whether my knives are substandard.

The tomato/bell pepper test is a reasonable test of sharpness. However the cutting stroke is important. At a microscopic level a knife edge is a saw, therefore you should be using a long cutting stroke that is at least 45 degrees in angle. If you hack straight down like an axe you're not actually getting very much cutting done, merely crushing with a sharp edge.

I work in a professional kitchen and sharpen my knives once a week. Whilst there are some easy to operate sharpening systems available that will get you a reasonable edge the only way to get knives really sharp is to use whetstones.

Katie H 03-10-2009 07:42 PM

Goodness, I don't sharpen my knives several times a week and my knives are USED a lot. Even after quite a while, they still slice tomatoes like a hot knife through butter. Perhaps you need to invest in a couple of very nice knives. You'll enjoy them.

Scotch 03-10-2009 08:17 PM

I agree about the tomato test. Your knife should pierce the skin and begin to slice the meat of the tomato when you simply draw it across the tomato's surface, pulling the blade toward you with little or no downward pressure.

I sharpen my knives infrequently but use the steel on them very often.

Teri's Therapy 03-10-2009 08:55 PM

Also, a clean tomato or pepper slices easier, get that wax off!

Rob Babcock 03-11-2009 03:01 AM

A good test is generally cutting what you normally will be cutting. Overripe tomatoes are a pretty good test- if you can slice them without crushing them you're sharp. I'll also see how thinly I can slice something; a knife has to be pretty sharp to get a very thin slice without tearing. Try cutting a lemon or onion thin enough to read a newspaper thru. Very finely sliced green onions are a pretty good test, too. Obviously cleaning cutting a pepper with the skin side up will tell you something but a knife that can't do that needs a lot of work

I agree that sharpening several times per week is overkill unless you're a butcher or work in a very high volume restaurant (or are a sushi chef, but I didn't get the sense that you are). You're really wasting a lot of steel, and if you're sharpening correctly they won't need to be completely resharpened that soon.

buzzard767 03-11-2009 08:43 AM

Quote:

Originally Posted by AlanS2323 (Post 801400)
What I would like to know is what is a reasonable sharpness? Is there some kind of test that's recognized to mean a knife is really, really sharp?

Everyone answered your first question. I'll answer the second. Tomatoes, lemons, whatever.... no two are the same so it is difficult to get a relative value. Many of us who are high end sharpeners use push cutting computer paper as a quick and easy test. I keep one ream of paper separate just for testing. This is as close to quality control as I can get so I have to live with any deficiencies. Orient the paper portrait style and hold it pinched between thumb and forefinger about a third of the way across the top. Place the knife blade on the top edge of the paper and push straight down with no sawing action. If it cleanly slices the paper along all points of the blade consider the knife very sharp. How sharp? It depends on how far away from the pinch grip the blade will cut cleanly. It's sharp at a quarter of an inch, but with proper blade geometry, proper steel, and super high grit polishing the results can be amazing. My personal record is 2 1/4" from the pinch and it was accomplished by the weight of the blade alone, no pushing. That's your definition of "really, really sharp".

Buzz

jasonr 03-12-2009 03:17 PM

Quote:

What I would like to know is what is a reasonable sharpness? Is there some kind of test that's recognized to mean a knife is really, really sharp?

If you find that your knife causes nuclear fission with each stroke, then it's probably too sharp :wink:

Personally, I have a Wustoff Classic set and I really can't get the things as sharp as I'd like, even though I apply the steel every time I use them and have used a ceramic sharpener several times on them.

But maybe it's for the best. I kind of like having all my fingers, so a duller knife may not be such a bad thing.

mike in brooklyn 03-12-2009 04:41 PM

When my knives get too far from sharp I take them to
a professional knife sharpener.
His 'acid' test of sharpness is to hold a sheet
of newspaper in one hand - loosely - and cut through it
with absolutely no pressure being exerted by the blade.

buzzard767 03-13-2009 05:56 PM

For you tomato slicers, I received a new knife last evening and put my edge on it today. I thought you might like to see what a really really sharp edge does to a tomato. I took a medium sized tomato, sliced the bottom to flatten it, and sliced it using nothing but the weight of the blade. Knife support was a light touch between thumb and fore finger to maintain a vertical orientation. One stroke forward, one half stroke back. DONE!

http://www.discusscooking.com/attach...95e912408d.jpg

http://www.discusscooking.com/attach...48f78afc98.jpg

AlanS2323 03-17-2009 01:39 PM

Quote:

Originally Posted by buzzard767 (Post 802210)
For you tomato slicers, I received a new knife last evening and put my edge on it today. I thought you might like to see what a really really sharp edge does to a tomato. I took a medium sized tomato, sliced the bottom to flatten it, and sliced it using nothing but the weight of the blade. Knife support was a light touch between thumb and fore finger to maintain a vertical orientation. One stroke forward, one half stroke back. DONE!

That's pretty amazing! What kind of knife is that? I'm guessing it costed a fortune?

AlanS2323 03-17-2009 01:41 PM

Quote:

Originally Posted by jasonr (Post 801925)
But maybe it's for the best. I kind of like having all my fingers, so a duller knife may not be such a bad thing.

I've heard dull knives are actually more dangerous because you wind up using all sorts of force and straining, which causes less precise control. Or maybe that's just what the knife salesman wanted me to think...

buzzard767 03-17-2009 01:52 PM

Quote:

Originally Posted by AlanS2323 (Post 803483)
That's pretty amazing! What kind of knife is that? I'm guessing it costed a fortune?

It's a 240mm Sakai Takayuki Grand Cheff (not misspelled). The blade is thin but not overly flexible and is made of Swedish Uddeholm AEB-L, the steel from which most safety razor blades are made. It has extremely small carbides making it easy to sharpen to very acute angles. I special ordered it through Seito Trading in NYC and paid around $175. The order was placed prior to 1-1-09 so the price may have gone up with the new year.

It's an unbelievably good knife.

Buzz

buzzard767 03-17-2009 02:00 PM

Quote:

Originally Posted by AlanS2323 (Post 803484)
I've heard dull knives are actually more dangerous because you wind up using all sorts of force and straining, which causes less precise control. Or maybe that's just what the knife salesman wanted me to think...

That is true. However, inattention or improper cutting technique will land you in trouble with a sharp blade. Redeeming factors are that the cutting won't hurt much if you feel it at all because it will be cleaner and the cut will heal both faster and with less scarring.

The bottom line is to have sharp knives and use them properly.

Buzz

AlanS2323 03-18-2009 12:55 PM

Quote:

Originally Posted by buzzard767 (Post 803488)
It's a 240mm Sakai Takayuki Grand Cheff (not misspelled). The blade is thin but not overly flexible and is made of Swedish Uddeholm AEB-L, the steel from which most safety razor blades are made. It has extremely small carbides making it easy to sharpen to very acute angles. I special ordered it through Seito Trading in NYC and paid around $175. The order was placed prior to 1-1-09 so the price may have gone up with the new year.

It's an unbelievably good knife.

Buzz

Thanks for details. I see that Seito Trading has the domain "sushiknives". Does that mean this knife is only meant for sushi? Is there some downside to using it for cutting meat or tough vegetables?

ChefJune 03-18-2009 02:22 PM

Quote:

Originally Posted by Andy M. (Post 801407)
It's not wrong or unreasonable to want sharp knives.

What's scary is that you have to sharpen your knives several times a week!

If you are referring to using a steel on the knife, that's not sharpening. I use a steel every time I use my knives. That's basic maintenance. If you're using some sharpening stone or tool that often, you need new knives.

I have a set of Henckels PRO S and sharpen them a couple of times a year. Any of my knives will easily cut through a tomato or bell pepper at any time.

What Andy said. But my knives are Wusthofs.

ChefJune 03-18-2009 02:24 PM

Quote:

Originally Posted by AlanS2323 (Post 801400)
So here's the thing...I have a cheap set of knives that I sharpen several times a week. I'm obsessive about them being sharp, but others have told me I'm being ridiculous and there's no need for a knife to be sharpened that often.

What I would like to know is what is a reasonable sharpness? Is there some kind of test that's recognized to mean a knife is really, really sharp? For me it's the tomatoes and bell peppers that get to me. If I have to apply pressure and really start sawing, I think the knives aren't sharp enough. Unfortunately, I've never gotten to that point with my knives...so I'm wondering if I just have impossible standards or whether my knives are substandard.

Curious, Alan, how you are holding your knife? That could be affecting your perception of sharpness.

buzzard767 03-18-2009 02:44 PM

Quote:

Originally Posted by AlanS2323 (Post 803777)
Thanks for details. I see that Seito Trading has the domain "sushiknives". Does that mean this knife is only meant for sushi? Is there some downside to using it for cutting meat or tough vegetables?

It's a Gyuto which literally translates as "cow sword". It's for veggies, fruits, and meats. It's a Chef's knife, except it has better geometry and the steel can take and hold a sharper edge.

Buzz


All times are GMT -5. The time now is 04:18 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.