How to Sharpen a Knife

How to Sharpen a Knife

Monday, September 26th, 2011

The first and most important thing to know about sharpening a knife is that if it needs to be sharpened then you have left it too long! What most people refer as sharpening a knife using a steel is actually honing a knife.

how to sharpen a knife
During everyday use the fine blade of a knife gets rolled or bent to one side (you probably would not be able to see this with the naked eye) so when you hone a knife all you are doing is pushing that edge back upright again.

Most knives are set with an angle at the point of 22 degrees. This is one quarter of a right angle. The more acute the angle the sharper the blade will be, but the more prone the edge will be to rolling over. To push the edge of the knife back to required angle you simply run the edge of the bladed along the steel. It is good practice to do this about 10 times on each side (alternating) every time you use the blade.

How do you know when a knife needs to be honed? Very simple … every time you use it!

If the knife has been dulled to the point where it cannot be honed then it will need to be sharpened, this is a much more aggressive act and actually involves grinding, scraping or rubbing away a small amount of steel to create a new edge. This can be done in any number of ways with wheels, stones and proprietary sharpening devices. With good quality knives that are used respectfully then sharpening does not need to be done very often and you might even consider getting it done by a professional. After using a sharpener you should always use a fine steel to clear any dust or crumbs of steel that might remain, remove any burs and ensure the edge is straight. It is always best to use water or meths when sharpening or grinding a knife – check with the instruction given by the manufacturer of the sharpener that you are using. Oil tends to be too heavy to allow any friction between the two surface – that is why we use it in our car engines!

How do you know if a knife needs to be fully re-sharpened? If you look along the edge and can see light reflected back at you then that is a good indication that it requires some attention.

How to Keep a Knife Sharp

Always store it in a knife block or knife holder – even putting it into a cutlery tray will dull the edge.
NEVER cut onto anything other than a chopping board – plates, ceramics, kitchen work surfaces will all wreck the blade of a knife.
Wash knives by hand – although stainless steel is dishwasher safe, the chemicals and action of the machine will not be kind to a fine blade.
Hone the blade every time you use the knife – this way it will need sharpening very infrequently.

This instructional video shows a method for honing a blade using a sharpening steel. Notice that throughout the video Gordon Ramsey refers to sharpening and not honing – but then you were never noted for being articulate – were you big man?

This second video gives some great background information about the process and also a little information about the design and construction of knives.

Remember – keep your knives in a knife block and keep then in good condition.