I briefly worked in a restaurant kitchen in Hong Kong under a British chef. He objected to the sound I made when slicing onions, and warned me not to be a 'board tapper'. I duly spent the next weeks learning to slice onions his way, though I wasn't able to match the speed I'd been accustomed to using the method I'm more practised in.
I've lived in Asia for many years, and use a Chinese vegetable knife/ Chinese chef's knife (CCK - NOT a cleaver) to cut almost everything. These tall, relatively straight-edged knives are used by Chinese chefs for the majority of tasks, and are employed using either a 'push cut' to force the blade through denser materials, a 'chop cut' in which the whole edge hits the board more or less parallel to it, or a 'draw cut' in which the tip of the blade is drawn back through softer materials, the angle at which the knife is held and the depth of the material being cut together determining how much of the edge's length does the cutting.
European chefs typically use French-/ German-style chef's knives with long, pointed, curved blades and favour a 'rocker' cut (during which the tip of the blade stays in contact with the board) for slicing medium-density ingredients like onions, as taught by Jamie Oliver et al.
The rocker cut is quiet and sustains high frequencies, although like the push cut it does require some vertical force from the cook's arm. The chop cut also sustains high frequencies and requires little force, relying instead upon a heavier blade to let gravity do the work, but it is noisy. (The draw cut is almost silent and can be very precise, but is slower partly because it requires the movement of the whole arm.) Each has its different applications.
Through some cursory research, I found out that tapping one's knife on the board even when not cutting anything can serve a number of functions:
- Activate muscle memory prior to cutting to avoid poor first cuts
- Remove pieces of food from the blade after cutting
- Warn others that a knife is about to be wielded
- Attract attention (valuable to street-kitchen chefs)
- Punctuate speech (valuable to television chefs)
- Add flair to one's work/ annoy people around one.
Whilst this kind of non-cut tapping is a separate matter, its various reasons cast light upon the types of issues surrounding human sounds in the kitchen, amid the roaring and grinding and hissing, churning, and beeping of various machines. Noise itself, clearly, isn't the problem.
I've come across the 'board-tapper' criticism elsewhere, in books, and often wondered whether this is mostly a tech thing (curved blades rock, straight blades tap), a culinary chauvinism thing (Asians tap, and cheap CCKs are not welcome in non-Asian kitchens), or a kitchen-hierarchy thing (chefs de commis should be seen and not heard).
As the extra noise probably equates to extra wear on the blade it could be a 'maintenance thing', and reasonably so were it not that most cooks don't sharpen other cooks' knives. Although the vast majority of jobbing chefs in the West use standard, serviceable implements made by the likes of Victorinox, not artworks of folded steel by artisan knifemakers, a heightened awareness of luxury goods everywhere has inevitably led to a heightened interest how they should be cared for - but as the explosion of interest in craft knifemaking has been very much an Internet-enabled phenomenon, its roots don't go back far enough to explain the prejudice. Outside of Japan, at least, using posh knives for mundane work is a relatively new thing.
Onions are onions everywhere... So why does board-tapping matter so much to some people?