How to sharpen a knife

Even the sharpest knife can become blunt after a while spent chopping, slicing and dicing. A blunt knife is of little use in the kitchen and can even be unsafe as it can slip off food and cut fingers instead.

With proper sharpening and maintenance, your kitchen knives will last for many years.

Sharpening versus honing

Confusingly, sharpening and honing are often used interchangeably when talking about knife maintenance, yet they are two different processes.

Sharpening involves adding a new edge to your blunt blade by removing some of its metal surface – albeit a very fine amount. This can be done with a whetstone or diamond stone, or proper sharpening steel. Alternatively, look for a professional knife-sharpening service, which can complete the task for you. Most professional chefs sharpen their knives only once or twice a year, so it’s not a chore you should need to do very often.

Honing is the straightening out of a blade’s edge. With use, your knife blade becomes misaligned, curling very slightly to one side so it doesn’t cut as cleanly through food and thus appears blunt. While honing a knife won’t give it a new edge but it will help it cut more easily. Most chefs hone their knives before every use. For home cooks, regular honing will keep knives in tip-top condition.

To do this, use a honing steel (often confusingly called a sharpening steel) – a long metal rod typically with ridges along its length. Many knife sets include a honing steel, or they can be bought cheaply online or in department stores.

How to use a honing steel

There’s no need to copy TV chefs who are generally seen whipping their knife back and forth across a honing steel at lightning-speed. For a safe way to hone a knife, follow these steps.

1. Place the tip of the honing steel on a worktop or chopping board – use a kitchen towel under the tip to stop it slipping – and hold the steel vertically.

2. Hold your knife comfortably in the other (dominant) hand. Place the knife next to the steel with the blade parallel to the steel and the edge pointing downwards.

3. Turn the knife so the edge is at a 20-degree angle to the steel. Using light pressure only, slowly draw the knife towards you down the steel, from the heel of the blade to the tip in one smooth movement. Put the knife on the other side of the steel and repeat the same movement at a 20-degree angle for the reverse of the blade.

4. Repeat this action four or five times on each side of the blade in turn.

5. Wipe the blade clean and you’re ready to use your honed knife.

TIP

Getting the angle right when using a honing steel is important otherwise you may damage your knife. As most knives have blades that are 20 degrees off from the vertical on either side, this is the correct angle to use with the steel.

But there’s no need to get a protractor out. To work out the right angle, start by holding your knife perpendicular (at a 90-degree angle) to the honing steel. Then tilt it halfway between being perpendicular and parallel to the steel, which puts the blade at a 45-degree angle. 

Tilt it halfway again between 45-degrees and parallel – you knife should now be about 22-degrees from the honing steel. The correct angle will seem as if you’re cutting a thin sliver from the honing steel when you draw the blade across it.