Knife Edge /Peter/

Let try to explain the knife’s edge and how it works. There are two basic types of blades for this discussion; there is the double-edged blade and the single-edged blade.

The double-edged blade on a knife is one of the most common shapes with 99% of all knives sold as V-shaped.

The single-edged blade is very different and is a Japanese invention. It is used by professionals mostly and is not found in many kitchens. It has a straight back at 90° with the other side having a single beveled chisel edge at 95° and is a more precise kitchen tool. The single edge has more metal supporting the cutting edge and it does not roll when cutting.

The straight backside 90° also has a slight concave back (urasuki) to help the cut go more smoothly aiding raw materials from sticking to the back side of the knife.

The cut of a single-edged blade is certainly more controlled and the hand movements and knife positions are different. For example if you would make very controlled roll cuts you need a flat side for more “turn control” and you can see this in this video:

My new knife Glestain has multiple bevels on one side and is their own design. This helps the same way as an urasuki and makes the knife “cut and glide”. This knife is razor-sharp and cuts through every vegetable like a scalpel but the reality is, while the cut is smooth it cannot cut as accurately as the single edge given it has a V-shape.

Imagine a knife under magnification and you would see on a single edge cut of a tomato. As it cuts downwards, it cuts through with tomato, and the back side maintains a straight cut at 90°. When you make the next cut, the remaining edge is straight for the last cut.

When the V-shaped cuts under magnification, it has two one 80° degree and one 100° and the point where it makes contact cuts unevenly. Essentially as it cuts it splits the tomato in two and leaves a v-shaped angle where it makes contact.

The last issue is more complex and not discussed by chefs and that is tension. The tension of the fruit/vegetable’s surface and mass.

The V-shaped is very practical and does not rust as easily, and with a Japanese knife made with higher carbon steel will rusts if you forget to wipe each and every time you make a cut.

I trust this helps….IMG_2066