Never put kitchen knives in the dishwasher – and other rules for keeping blades sharp

By Sue Quinn

Many of us own at least one decent kitchen knife and know the pleasure of being able to slice through all food like butter.

The problem is, even good knives don't sharpen themselves – a fact that many of us ignore.

And while blunt blades can badly crush ingredients and make slicing and chopping tricky, they can also slip and even cause injuries.

READ MORE: Secret ingredient that makes this the best Bloody Mary ever

We've consulted leading experts on the best way to use, wash, store and sharpen your knives to prevent damage, make them last longer, keep them safe to use and generally get the best out of them.

How to store knives

Are you storing all your knives together in a drawer?

"That's a disaster because they'll be bashing against each other," says Corin Mellor, knife designer and creative director at David Mellor, the luxury tableware and kitchenware retailer.

"If the edge is sharp, it will just be battered off."

Many chefs favour knife rolls, the portable fabric or leather cases with pockets that keep knives secure and prevent blades knocking against each other.

If these seem a bit cheffy, opt for a wooden knife block. "The edges of the [wooden] slots are very soft, so they don't abrade the knife," Mellor says.

READ MORE: Ingredient hidden in this delicious dish might shock you

Experts also recommend magnetic strips or boards that hold knives flat.

"Some of them have a very rough surface that can damage the blade as you take the knife off, so go for boards where the magnet is set behind wood or silicone," Lohse recommends.

If you have young children, consider whether this is a safe option for knife storage in your kitchen, or position it where small hands can't reach it.

READ MORE: 95c pantry staple celebrity chef swears by in show-stopping dish

How to clean knives

Can dishwashers damage knives? The answer is yes. A combination of harsh dishwasher tablets, salt and lengthy periods sitting in damp air can corrode the blades.

"We always recommend hand washing with regular dishwashing liquid and also drying knives as soon as possible once clean," Mellor says.

The higher carbon content of good kitchen knife steel is slightly more susceptible to corrosion than regular stainless steel, he says.

"Dishwashers encourage leaving knives in a warm, damp environment, which is ideal for the early stages of corrosion. Plus, the abrasives used in dishwasher tablets dull the cutting edge."

Use the right cutting surface

Consider your chopping board. Glass (bizarrely popular), marble or any other surface with no 'give' in it will blunt a knife quicker than you can say julienne.

"You're literally ruining your knife every time," says Mellor.

Wooden chopping boards are best. "And end-grain wooden boards are ideal," Mellor says.

"The end grains are wood fibres that are sticking up vertically like a soft cushion that the knife blade can, in effect, sink into."

End-grain chopping boards, also known as butcher's blocks, can often be identified by their checkerboard pattern and a price tag that's higher than standard wooden chopping boards.

Stick to the stated purpose

Other ways to help give your knives a long and healthy life?

Don't be tempted to use them for anything other than their stated purpose, says Kristin Lohse, cookware and knife expert at online cookware and ingredients specialist Sous Chef.

"Don't use them on frozen food or bones unless it's specifically mentioned [by the manufacturer] that they're suitable for that," Lohse says.

"And never use them as a lever to open tins, for example, or cut through aluminium foil."

How to sharpen knives

Steer clear of pull-through knife sharpeners, the ones that grind both sides of the blade simultaneously, says Matthew Nash, who runs the Sharpening Service UK, a mobile and postal sharpening service and training school.

"The biggest problem with them is that they're very aggressive and remove a lot of metal without necessarily sharpening the knife," he says. "I would never advise anyone to use them."

READ MORE: Gift ideas for the Pilates girlies in your life, according to an instructor

Nash recommends whetstones, blocks of abrasive material that are available in sets of different grit sizes, or as single whetstones with coarse grit on one side, and finer grit on the other.

The coarser grit is used first to abrade the knife edge, and the finer grit is used to polish and finish the sharpening process.

"The coarse grit makes it sharp and does most of the work, and the finer grit makes it sharper," Nash says.

Step-by-step technique for sharpening knives on a whetstone:

1. Prepare the whetstone

Wet the whetstone with water or rub it with specialist oil. "It takes the friction out and allows the stone to work the blade smoothly, rather than the blade grinding the stone," Nash says.

(Contrary to popular belief, whetstones get their name from the old English word hwettan, meaning "to sharpen", not the word "wet".)

2. Pull don't push

Hold the heel of the knife – the part of the blade closest to the handle – at an angle of 15-20 degrees against the whetstone.

"Pull the knife towards you to the tip, applying even pressure," Nash says. "Never push the cutting edge of the knife into the stone or you'll put a gouge in it."

3. Raising a burr

Once you have run the knife over the whetstone a couple of times, check for the "burr". This is the raised fold of metal that forms along the opposite side of the blade to the one you have sharpened.

READ MORE: How a bag of frozen peas could save your dog's life

To check for this, run your thumb down the opposite side of the blade and you should feel it "catch". If you can't feel the burr, continue running the blade along the whetstone until you can.

Note: Never run your thumb along the actual sharp edge.

"How much you need to sharpen the edge depends on the quality of the whetstone, the quality of the stone and how sharp it is.

You need to work the knife until you've got a burr," Nash says. Once you can feel the burr, turn the knife over and repeat the process on the other side.

4. Removing the burr

To finish, run the knife along the fine whetstone (or the finer side of a dual-sided whetstone), using the same method as before, to flatten out and remove the burr and leave the knife sharp.

READ MORE: Meghan's solo appearance as Harry addresses marriage rumours

Honing steels

You've probably seen chefs on the telly using a honing steel or honing rod, where they very quickly swipe the knife multiple times against the steel.

This has nothing to do with sharpening the knife, Nash says.

"It straightens the edge of the knife but will never sharpen it."

He doesn't recommend using one unless you're a professional or unless the steel is made of ceramic.

"You'll just damage your knife," he says.

© Telegraph Media Group Limited 2024

FOLLOW US ON WHATSAPP HERE: Stay across all the latest in celebrity, lifestyle and opinion via our WhatsApp channel. No comments, no algorithm and nobody can see your private details.