Cutting edge: How to chop like a pro

Even some of the best home chefs lack knife skills. But slicing and dicing can be a breeze

Marianne Lumb and Fuchsia Dunlop, world-class experts respectively on Western and Chinese cooking, have just finished demonstrating knife skills to a group of 20 people. Everyone had watched in fascination while fish were filleted, onions chopped to the size of match-heads, and white radish sliced paper-thin. When they were done, I asked one of the group if she had learned any new techniques. She had learned plenty, "and I'm inclined to try some of this".

Is this a novice cook speaking? No. It is Elaine Hallgarten, a member of the Guild of Food Writers (which ran the demonstration as a workshop for its members) and the author of eight cookbooks. When it comes to knife skills, even seasoned cooks have a lot to learn from the experts.

Knife skills are the single most important area of kitchen knowledge, yet the subject is usually ignored in cookery books and recipe columns. We're just expected to have been born with the skills. But we weren't.

I got vivid proof of that at another event the day after the one run by the Guild of Food Writers: the inaugural knife skills class at the new Waitrose Cookery School in north London. Instructor Gordon McDermott, an improbably likeable and charismatic teacher, had a roomful of home cooks who were clearly desperate for knowledge. One of them said to me that her poor knife skills "limit the things I can do". And she wasn't the only one seeking knife knowledge. At the long-established Leiths School of Food and Wine, knife skills sessions are among the most popular half-day classes.

Knife skills can be broken down into three areas: choosing, using, and caring. Here's a brief rundown.

Choosing

You don't need dozens of knives. An all-purpose chef's knife is the essential, with 12.5cm the minimum length. Marianne Lumb, winner of 2009's Masterchef: The Professionals, and Gordon McDermott agree that the chef's knife could be the only knife you need. "One decent knife can do just about anything."

But two others could also be regarded as essential. A small, thin paring knife is perfect for fine work and will be essential for most cooks. You can slice bread easily only with a serrated bread knife. Everything else is optional.

Japanese knives are in vogue at the moment and have a lot to recommend them, but they are mostly thin-bladed slicing knives rather than heavy-duty chef's knives. The best place to buy is at one of the London stores of the Japanese Knife Company. Fuchsia Dunlop uses Chinese cleavers for nearly all her kitchen work, but remember that she studied cooking at a professional school in Chengdu.

On one matter all professionals agree: knife choice is a very personal thing. "Think about how different our hands are," says Marianne Lumb. Corin Mellor, of the famous David Mellor Design company, agrees: "You have to pick it up, and our staff are trained to make sure this happens. It's about what you like." This means that you have to buy at a shop; online shopping will not do.

Using

The knife skills programme at the Waitrose school is structured around preparing, cooking and eating actual dishes. When I watched the students cutting up their ingredients, I saw that even experienced home cooks may never have learnt how to hold a knife. And bad habits die hard. After Gordon McDermott demonstrated the correct way, many students immediately reverted to their old grip.

So what was he doing? For most chopping and slicing, the correct approach to a kitchen knife is, as Marianne Lumb put it, to hold it "as if you were shaking hands with it". Many home cooks put their index finger on the back of the blade, but this is inefficient and cumbersome.

The handshake grip leads naturally to the "rolling chop" motion that most chefs regard as the best all-purpose chopping technique. Keep the tip of the knife on the chopping board. Push the knife blade down and forward at the same time, so the blade moves through the food and doesn't simply land flat on the board. Chopping this way is easy – as long as your knife is sharp (keep on reading).

What about the other hand, the one holding the food while you chop? It should form a claw: fingers and thumb turned inward so the tips get nowhere near the knife. If you hold the knife blade against the knuckles of your first finger joint, and never raise the blade higher than the second knuckle, it is difficult to cut yourself.

The handshake is not necessarily best when using small knives for fine work such as coring tomatoes or slicing shallots. The fingertip on the back of the blade is allowed here – but try the handshake if you're not used to it. Some people find it works better.

After a while, the Waitrose students were clearly making progress. They stuck with what Gordon had shown them, and they started feeling the difference. "I tried it my way, and I tried it his. His is better." She knew it would take time and practice, but felt undaunted: "You watch it being done properly and then you go home and do it the same way."

Taking care

The most expensive knife in the world becomes a useless slab of metal if you don't keep it sharp. And dull knives are not just harder to use than sharp ones but more dangerous.

You can tell whether your knife is sharp simply by using it. McDermott and Lumb both say that "a sharp knife does the work for you". You need little pressure to get the blade sliding easily into and through the onion, rack of lamb, carrot. Unsharpened knives are dangerous: hard pushing with a dull blade makes slippage more likely.

That's why every knifing professional repeats the standard mantra: sharpen little but often. Marianne Lumb refers to this as "staying on top of it. This is a real discipline, but when a knife loses its edge, it loses its soul." A few gentle swipes of the steel along the full length of the blade – that's all you need to sharpen.

Sharpening has a reputation for being difficult, but it's easy, once you've got the knack . Go to a friendly butcher, fishmonger, or restaurant and ask them to show you how.

There are three sharpening choices. Whetstones are best, but hardest to master. A standard steel is easier once you get the hang of it; ceramic is best, diamond second best. Finally there are sharpening machines, with steels or wheels set at pre-set angles to sharpen both sides of the knife as you draw the blade through. The Chantry knife sharpener is one of the most widely available. Ceramic wheels are better. Corin Mellor thinks many home cooks are best off using a machine if the alternative is bad sharpening with a steel.

What's the correct angle for sharpening if using a steel or whetstone? Marianne Lumb says it's 10-20 degrees to the blade. Corin Mellor says 28.5. Gordon McDermott says 35. Hooray! There's margin for error. That should take some of the fear out of the process. Don't worry too much about precise angles, as long as you use your chosen sharpener little but often.

Knife care extends to what you do with them when they're not in use. Wash them with soap and warm water, and dry immediately. If you are leaving knives to air-dry, don't place them tip-down in a cutlery basket and don't let the blade rub against metal.

Storage is crucial. Keep knives on a magnetic rack or in a knife block. Storing them in a drawer will bring the edge into contact with other metal utensils, and this will blunt them.

After years of regular use, any knife will reach a point where it can't be sharpened to produce an optimum cutting edge. This is when you need to replace it. Just make sure you stay on top of your new purchase from the very beginning.

The bottom line

Watching television cookery shows might make you think that knife skills reside in machine gun-speed chopping. Chefs chop that way because their customers will go hungry if they don't. In the home kitchen, there's no need for that speed. The aim is to cut correctly. Gordon McDermott repeatedly tells his students to slow down and get the motion right. Fuchsia Dunlop speaks of the "rhythm and meditation" of proper knife use. As you practise doing it the right way, you will also find yourself getting faster.

But you'll never be as fast as chefs who cook professionally for 70 hours a week. If you want to try, then give it a go. Just be aware that you are missing the point and have a plentiful supply of plasters.