Before I even begin I’ll admit that this is more of an academic discourse than a practical one. Of course, you need a sharp knife to do your work in the kitchen. But I do love to question conventional wisdom and along the way, we may reveal some practical considerations.
You have probably heard chef’s say that you are more likely to cut yourself with a dull knife than with a sharp one. Why? Well, the reason given is because when you, for example, slice vegetables with a dull knife you have to exert more downward pressure to cut through the food and your knife also fails to make purchase on the food, making it more prone to slipping. So, a dull knife means you put more pressure on the knife and the knife is harder to control, meaning it may slip and cut your finger or hand.
The solution? Well, most people say the solution is to have a “razor sharp knife.” I actually think that you do not need a razor-sharp knife for everyday use. A chef knife, your main kitchen knife, needs to be sharp enough to do the job efficiently and with control but unless you need to do paper thin slices, you probably don’t need it to be as sharp as a razor.
A razor sharp knife or any very sharp knife is very likely to cut you unless you are being very careful all of the time, and minding all of your knife safety rules. I can tell you, anecdotally, that I’ve been cut more often with a sharp knife than with a dull one. Even the slightest inadvertent contact with a very sharp knife edge will cut into your skin, just as the edge of a piece of paper will cut with the slightest pressure.
So, are you more likely to cut yourself with a dull knife? This is an assumption based on the utility of the knife and I do not think such an assumption is warranted. You are probably not more likely to cut yourself with a knife that is dull.
However, due to the added pressure you exert on the blade of a dull knife, you are more likely to cut yourself badly. In other words, while you can still, of course, cut yourself with a sharp knife, you may be exerting much less pressure and get a small clean cut more analogous to a paper cut.
But, at the same time, a knife that is improperly sharpened, with part of the edge very sharp and other parts dull or jagged, so that the knife hangs up, can cause very bad cuts! A knife like this may begin slicing through with ease, then hang up, causing you to exert more pressure before beginning the knife begins to cut again and moves through very quickly. This can cause slippage and when the sharp blade hits your skin, the cut could be very bad.
On the other hand, a dull knife is still a dull knife. It may not be any better at cutting your finger than it is at cutting a cucumber or carrot.
A Properly Sharpened Knife is More Important Than a Razor Sharp Knife
A good way to test whether your knife is properly sharpened is to do a paper slice in the air. Hold a piece of paper up in front of you and slice through the edge of the paper, starting with the back of the blade and slicing through to the tip. If the knife does not easily slice the paper, it probably is not sharp enough. If it slices through and then gets hung up at any point and begins to tear rather than cleanly cut the paper, you have discovered a problematic area on the edge. I like to use colored paper for this purpose, as it will leave little bits of paper on the part of the blade that needs work and if the paper is colored these bits are easier to see.
There is no real point to having a razor-thin edge on your chef knife. Such an edge will simply be harder to keep sharp as the very thin edge will take damage easier or, depending on the metal, roll over quite easily. Sharp enough is sharp enough. I know there are many sharpening articles and YouTube videos which focus on getting your knife to a razor edge, but this seems to be designed to get traffic and to satisfy an unfounded need for perfection that, in the end, is overkill. You’re not going to shave with your kitchen knife, are you? I can make extremely thin slices of tomato with my chef knife which is sharpened on a whetstone like this 1000/6000 Grit Whetstone from Home Pro Shop, even though the knife is probably not as sharp as a razor. And I am not an expert sharpener, I’ll readily admit.