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How To Sharpen a Knife

If you’ve used a good quality sharp knife before, you’ll know what a difference it makes to food preparation. Keeping your knife sharp will prolong its lifespan, be more pleasurable to use and be much safer than a blunter knife.

Below, we have compiled some information that will be useful to those new to knife sharpening techniques.

What methods are there?

Manual ‘Draw-Through’ Sharpeners

If you don’t want to learn how to use a sharpening steel or whetstone, manual ‘draw-through’ sharpeners offer an easy and effective alternative. You simply place your knife blade into the slot in the sharpener and draw it forwards and backwards. This rubs the knife blade edge against abrasives (that are set at a precise angle), sharpening it back to its former glory in a few easy strokes!

Abrasives used vary from steel to ceramic to surfaces covered with fine diamonds. Harder knives require harder abrasives to sharpen them, so if you have a very hard knife (like the Japanese knives) you will need a sharpener with ceramic or diamond abrasives.

Electric Sharpeners

Pretty similar to manual ‘draw-through’ sharpeners, electric sharpeners use abrasives set at a precise angle to sharpen a knife edge. The difference is you don’t need to draw the knife forwards and backwards through the machine because the abrasive belt or wheels are powered. Electric machines produce very accurate results and are quick and easy to use. Make sure you don’t over sharpen your knife through – it only takes a few strokes, more than this may wear away more metal from your knife than needed.

Sharpening Steels

Probably the first image that comes to mind when you think of sharpening a knife is that of a sharpening steel. If you don’t know how to use one, it’s relatively easy to learn and something you can master fairly quickly - just check out our tips further down in this section.

Sharpening Steels are most commonly made of steel (hence the name), but you can also get ceramic or diamond coated ones, which may be more suited to your knife.

Steel rods ‘hone’ a knife: a knife’s edge is made up of what looks like tiny teeth and these get bent when the knife is used. A steel rod will straighten these back out, making the knife sharp again. So it’s best to use a steel rod regularly to maintain a sharp edge.

If your knife is really blunt, you’ll need to use a diamond or ceramic rod (or one of the other sharpening methods) to get it sharp again.

For harder knives - such as Japanese ones - you’ll need a ceramic or diamond coated rod to sharpen your knife.

Whetstones

A whetstone is a little block (a bit like a small brick) that was traditionally made of natural stone, but synthetic versions made from various materials are also available.

A whetstone can give a knife a tremendously fine edge, and for this reason, is the most commonly-used method in Japan, where a super-fine cutting edge is needed for the cuisine.

Whetstones range in their level of abrasiveness depending on the size of the grit in the stone. A 300 grit stone will be very abrasive and used to start to get a very blunt knife back to shape, while a 4000 grit stone will be for super-fine honing and making a knife edge extremely sharp.

Usually, you need to wet the stone before use, then you run the edge of the blade back and forth over the stone. It takes a bit more practice to master this method of sharpening, but it’s very rewarding and will leave you with the finest edge possible. See below for tips on using whetstone sharpeners

Serrated Knives

Serrated knives do not need to be sharpened in the same way that smooth-edged knives do; with a serrated blade the teeth ‘tear’ the food, so a serrated blade’s sharpness isn’t the most important thing.

It won’t be possible to sharpen a serrated blade back to its original condition, but you can help it out a bit from time to time. A sharpening rod can be used between the teeth to give the blade’s sharpness a boost.

Our advice is to only use a serrated knife for what it was intended, (e.g. don’t use a bread knife to saw through a shoulder of lamb!) in order to prevent the edge from becoming dull.

How do I use a sharpening steel?

It may look daunting, but using a sharpening steel is quite an easy skill to learn and once you’ve got the hang of it, it will become second nature. We suggest you practise on a knife you’re not too fond of to start with and when your technique clicks into place, you’ll be able to unleash your new sharpening skills on your favourite kitchen knives without worrying.

Before you start, remember:

Steel sharpening rods are designed to ‘hone’ rather that sharpen a knife. This should be enough to return your knife to its former glory, but if your knife is really blunt, you’ll need to use a diamond or ceramic rod or a different sharpening method to re-sharpen your knife.

Japanese-style knives are harder and thinner, so to sharpen one of these with a sharpening rod, you’ll need a ceramic or diamond-coated one.

Your sharpening steel should be at least as long as the knife blade you want to sharpen – if the sharpening steel is shorter, you’ll be making the task a lot harder for yourself.

Don’t worry about speed too much – it’s more important to get the action and angle right. Once you’ve got the hang of it, you’ll be able to speed up (and impress people with your skills).
And that’s it! Now you can enjoy having a super-sharp knife, happy in the knowledge that you did it yourself.

How do I use a Whetstone?

If you want to achieve the sharpest of edges, a whetstone will be your best bet. It takes a little longer to master but can be immensely satisfying. And once you know what you’re doing, it only takes a couple of minutes too!

Usually, you need to soak the stone before use, but some manufacturers offer alternatives so follow the preparation instructions that come with your whetstone.

Put the whetstone on a cutting board or solid surface. For extra stability, you could put a wet paper towel under the stone to keep it in place.

Hold your knife by the handle and place the edge (point first) against the top surface of the stone. Hold the knife so the blade meets the stone at an angle – usually about 20 degrees for a Western knife and 10 degrees for a Japanese knife.

Making sure you maintain this angle, run the edge of the blade back and forth over the stone’s surface. You don’t need to press too hard – just apply a little bit of pressure and let the abrasiveness of the stone do its work.

Do the same thing on the other side of your knife and repeat on alternating sides until your knife is sharp.

Rinse your knife under the tap and wipe it dry with a towel to remove any tiny metal filings.

So there you go! A little information to get you on your way. We hope you learned something here.