Before we talk about the blades and shapes, it is worth talking about the material. The majority of the knives is made out of steel. However steel to steel is very different. The basic steel is made of Iron (Fe) and Carbon (C). The ratio of these two elements will determine many of their properties. The higher the ratio the more brittle the knife will be. It also will be harder, more durable and less flexible. On the other side a low carbon steel will be soft, pliable and flexible. Both types will however rust. So in order to avoid rusting Chromium (Cr) is added. For longer lasting and durability titanium (Ti) is added. For a more light weight knife, Magnesium (Mg) is added. Currently there three common alloys used in the knives.
- Carbon Steel: An alloy of carbon and iron, it is traditionally used for blades because it is enough to be sharpened easily. It corrodes and discolors easily, however, especially when used with acidic foods.
- Stainless steel: It will not rust, corrode discolor and is extremely durable. But stainless steel blade is much more difficult to sharpen than a carbon steel one, once the edge is established, it last longer than the esdge on a carbon steel blade.
- High Carbon stainless steel: An alloy combining the best features of carbon steel and stainless steel, it neither corrodesnor discolor and can be sharpened almost as easily as carbon steel. It is now the most frequently used metal for blades.
- Sandwich blades: Very frequently used in Japanese knives. A carbon steel blade sandwiched between two stainless steel sheets, exposing only the edge. It combines the best of both worlds, but it is labor intensive to manufacture so they are not as popular.
Recently the last 15 years or so, there are ceramic knives in the market. Ceramic blades are sharp and remain sharp for ever, but can break very easy and since they are white they stain very easy.
The next important factor other than the material is the method of production. This will determine to the great extend many of the knife properties. The oldest method is the stamped method. It is basically starting with e basic blade shape that it is either cut out from a sheet of steel (the more common method nowadays) or it is poured into a mold from a molten steel (the more common method in older times). The blade then is sharpened to an edge. This method, since the material is required to be in a sheet form, gives a somewhat flexible knife that can bend. The blade is usually very thin easily used more bulky materials like cheese wheels and big chunks of meat. The other method is the forged method. Here the basic blade is curved out from a block of steel (stock removal method). Occasionally the blades can be made by hammering the metal (actual forging method). This results in a thicker, heavier blade, that give the knife body and weight that can result in better more efficient cutting on cutting boards.
With materials, production methods and blade shapes, out of the way let’s now focus on the actual knife. The actual knife that regardless the applications will have some or all of the following characteristics. (image and table from wikipedia)
APoint:The very end of the knife, which is used for piercingBTip:The first third of the blade (approximately), which is used for small or delicate work. Also known as belly or curve when curved, as on a chef’s knife.CEdge:The entire cutting surface of the knife, which extends from the point to the heel. The edge may be beveled or symmetric.DHeel:The rear part of the blade, used for cutting activities that require more forceESpine:The top, thicker portion of the blade, which adds weight and strengthFBolster:The thick metal portion joining the handle and the blade, which adds weight and balanceGFinger Guard:The portion of the bolster that keeps the cook’s hand from slipping onto the bladeHReturn:The point where the heel meets the bolsterJTang:The portion of the metal blade that extends into the handle, giving the knife stability and extra weightKScales:The two portions of handle material (wood, plastic, composite, etc.) that are attached to either side of the tangLRivets:The metal pins (usually 3) that hold the scales to the tangMHandle Guard:The lip below the butt of the handle, which gives the knife a better grip and prevents slippingNButt:The terminal end of the handle
The purpose of the honing steel is to straighten the edge and not to sharpen. Start with the knife on an angle going from top to bottom like trying to peel the steel 5 times on each side. Repeat for 4, 3, 2, 1 till you are done. Sharpening now is the damage shown in C to D where the blade has actually chipped off, missing material and therefore it has lost its cutting edge (!). This is fixed with material removal and only. No honing. Although there are in the market many sharpening devices, I am not going to talk about them. Sharpening is something that should be done with grinding wheel by professionals. There are no devices that can substitute either of the two.
With these on mind we can now see the more specific knives that are required for each job and creat a home arsenal of knives that can deliver cutting edge where needed. Stay tuned for more knives to come.