Sharp is good. It allows for more precision and also ensures the knife goes where you want it to – a blunt knife skidding off carrots and onion skins is exponentially more dangerous than a sharp one travelling correctly.
There are several factors to consider here, not least that it’s perfectly possible to give an awful bit of steel a very sharp edge – it’s keeping it that way that poses the challenge.
You can help yourself enormously by learning the difference between sharpening and honing, and investing in a good chopping board. But most importantly try to find a knife with a Rockwell ‘C’ hardness of between 58 and 62. Much below this number the blade is too soft and will deform quickly and be reluctant to hold an edge, while too far above it and we enter the world of brittleness and blades that require the strength and tenacity of Hercules sharpen.
You will no doubt come across the phrase ‘carbon steel’ as a euphemism for the type of steel that rusts. All steel contains carbon (and iron), otherwise it wouldn’t be steel. Stainless steel also has varying amounts of chrome that forms a bond with oxygen and creates a corrosion-resistant layer. The amount of carbon in the steel will influence its hardness and brittleness, so one should look for a pretty solid amount. If your preferred knife maker has their product description approved by their engineers, then look for a ‘High Carbon’ blade, as this will contain between 0.6 and 1% carbon and is perfect for a chef’s knife. If the only description is provided by the marketing department, then either take your chances or look elsewhere.
In general, if you find that your knife maker uses lots of random letters jammed together to describe their steel (XMov58Cr291c) then avoid.
You may also come across the old myth that non-stainless steel is better at gaining and retaining an edge than stainless steel. Very possibly 20 years ago this was true on occasion, and even today the very worst stainless steel is horrific. Overall, however, this idea is rubbish – the best steels of both types are almost incomparable in terms of blade suitability, it’s just a question of whether you want a knife that rusts or not.
The other hugely significant aspects of a knife to consider are comfort and balance. Held properly, a good knife will feel like you can use it for hours at a time, with neither the handle nor blade feeling heavier than the other. You may struggle to achieve this with outlying knives like cleavers and parers, but a good chef’s knife should balance easily on your forefinger when positioned underneath the top of the handle.
Overall weight should also be considered, with a light yet robust knife generally preferable to a heavy one. A lighter knife is less tiring and wielded more dextrously, whereas a heavy knife is clumsy and often sees its weight trying to compensate for a poor edge. On the flip-side, a plasticky and insubstantial £10 effort will also be of not much use.
Of course, given that making a heavy knife is a lot easier than a lighter one, the marketing departments are once again out in force covering for the sins of their designers. Ultimately the right feel of the knife is simply that which appeals to you the most – if you’re spending more than £100 on a chef’s knife make sure you have the opportunity to hold it, and ideally test it on a carrot.
So now you have a knife that’s sharp – and stays that way – and feels good to hold. The last, and most subtle factor to consider is the geometry of the blade, by which we mean the cross-section seen if the blade were to be broken in half.
Almost all knives have a ‘flat grind’ where the sides of the blade run in a flat line from the edge of the spine to the tip. This is generally perfectly acceptable, but is the norm more because it’s easy to make than anything else. A flat blade needs to have a thin spine if it is to have a light and nimble blade, which can cause issues with rigidity if the knife is not made well. A thick spine will reward you with surer cuts and precision, but will up the weight of the knife. It will also mean that as you sharpen your knife over the years the blade will get thicker and thicker, and so less pleasing to use.
Some knives will have a very slightly convex grind, which will work beautifully when the knife is brand new but will degrade rapidly as you come to sharpen and remove material.
The last option is for a ‘hollow grind’, where the knife has a concave aspect. This allows for the knife to have a substantial spine if required, while the business end of the blade will be pleasingly thin and won’t thicken as you sharpen it. Alas, very few knives are made this way as it’s complex and challenging to make consistently.
Possibly all this talk of grinding is a little too arcane, but if nothing else it pays to look at a knife at more angles than the rote sideways shots presented on most websites.
Now that you know what to look for, let’s take a look at the topic of caring for your knife.