Kitchen knife


A kitchen knife is any knife that is intended to be used in food preparation, as opposed to a table knife used when eating, as part of a set of cutlery. While much of this work can be accomplished with a few general-purpose knives — notably a large chef's knife and a smaller serrated blade utility knife — there are also many specialized knives that are designed for specific tasks such as a tough cleaver, a small paring knife, and a bread knife. Kitchen knives can be made from several different materials, though the most common is a hardened steel blade with a wooden handle.
Historically, knives were made in "knife cities" that are noted for being the best at their production in that country with the pre-emininent, in Europe, being: Sheffield in Yorkshire, North of England; Thiers, Puy-de-Dôme in the Auvergne of France; Solingen in the Northern Rhineland of Germany; and Eskilstuna of Södermanland in Sweden. Each of these produced knives in a styles particular to the city, with Thiers especially being noted for the French point of Laguiole and steak knives. Whereas in Japan, there are many dispersed centres of kitchen knife production due to diversification that followed in wake of legislation restricting the production of sword-making. These are Tsubame-Sanjō in Niigata Prefecture, Seki in Gifu Prefecture, Sakai in Osaka Prefecture, Takefu-Echizen in Fukui Prefecture, and Tosa in Kōchi Prefecture amongst a number of others. Each area have their own style of knife, with Sakai in Osaka favouring the "sheep's foot" or drop point, in contrast to the square-tipped style of Edo, modern-day Tokyo.

Construction

Material

  • Steel is an alloy of iron and carbon is the commonest of blade materials and comes in many forms:
  • *Carbon steel is an alloy that often includes other elements such as vanadium and manganese. Carbon steel commonly used in knives has around 1.0% carbon, is inexpensive, and holds its edge well. Carbon steel is normally easier to resharpen than many stainless steels, but is vulnerable to rust and stains. The blades should be cleaned, dried, and lubricated after each use. New carbon-steel knives may impart a metallic or "iron" flavour to acidic foods, though over time, the steel will acquire a patina of oxidation which will prevent corrosion. Good carbon steel will take a sharp edge, but is not so hard as to be difficult to sharpen, unlike some grades of stainless steel.
  • *Stainless steel is an alloy of iron, approximately 10–15% chromium, possibly nickel, and molybdenum, with only a small amount of carbon. Typical stainless steel knives are made of 420 stainless, a high-chromium stainless steel alloy often used in flatware. Stainless steel may be softer than carbon steel, but this makes it easier to sharpen. Stainless steel knives resist rust and corrosion better than carbon steel knives.
  • *High-carbon stainless steel is a stainless steel alloy with a relatively high amount of carbon compared to other stainless alloys. For example, AISI grade 420 stainless steel normally contains 0.15% by weight of carbon, but the 420HC variant used for cutlery has 0.4% to 0.5%. The increased carbon content is intended to provide the best attributes of carbon steel and ordinary stainless steel. High carbon stainless steel blades do not discolour or stain, and maintain a sharp edge for a reasonable time. Most 'high-carbon' stainless blades are made of more expensive alloys than less-expensive stainless knives, often including amounts of molybdenum, vanadium, cobalt, and other components intended to increase strength, edge-holding, and cutting ability.
  • *Laminated steel blades combine the advantages of a hard, but brittle steel which will hold a good edge but is easily chipped and damaged, with a tougher steel less susceptible to damage and chipping, but incapable of taking a good edge. The hard steel is sandwiched and protected between layers of the tougher steel. The hard steel forms the edge of the blade; it will take a more acute grind than a softer steel, and will stay sharp longer. The core and the spine of the blade of soft steel — tough and resilient, but flexible — will normally make up most of the blade and the flats or sides will be either a medium or hard steel to give a good surface that can take finish, such as a hammered surface. All these blade sections are forge-welded together. In Japanese blades, this construction is known as san mai,. Lamination can also be achieved through the time-consuming multiple folding of a two or more pieces of steel — at least one a high quality hard steel and another a tough and resilient soft steel — that is forge worked many times over, refolding until dozens of layers are made across the thickness of the blade and the surface is then acid-etched to bring out the pattern of marbling, as found in the high quality Damascus steel blades.
  • Titanium is much lighter and highly corrosion-resistant, but not harder than steel. However, it is more flexible than steel, especially in alloy, when doped with elements like nickel. Titanium carbide and titanium nitride are both very hard and coatings or inclusions of these may be added to the edge of the blade, but they are greatly prone to fracturing and chipping. Titanium does not impart any flavour to food. Typically, it is very expensive and not well suited to kitchen cutlery, so not widely available.
  • Ceramic blades are made from sintered zirconium dioxide, and are very hard, but brittle, retaining their sharp edge for a long time. They are low in mass, do not impart any taste to food and do not corrode. They are suitable for slicing fruit, vegetables, and boneless meat. Ceramic knives are best used as a specialist kitchen utensil. Manufacturing improvements have reduced the brittleness, but because of their hardness and brittle edges, sharpening requires specialist equipment and techniques.
  • Plastic blades are usually not very sharp and are mainly used to cut through vegetables, especially salads, without causing discolouration. They are not sharp enough to cut deeply into flesh, but can scratch or even possibly cut skin, so are often used for children's training knives.

    Blade manufacturing

Steel blades can be manufactured either by being forged or stamped.
  • Hand-forged blades are made in a multi-step process by skilled manual labor. A piece of steel alloy is heated to a high temperature, and pounded while hot to form it. The blade is then heated above critical temperature, quenched in an appropriate liquid, and tempered to the desired hardness. Commercially, "forged" blades may receive as little as one blow from a hammer between dies, to form features such as the "bolster" in a blank. After forging and heat-treating, the blade is polished and sharpened. Forged blades are typically thicker and heavier than stamped blades, which is sometimes advantageous.
  • Stamped blades are cut to shape directly from cold-rolled steel, heat-treated for strength, then ground, polished, and sharpened. Stamped blades can often, but not always, be identified by the absence of a [|bolster].

    Type of edge

The edge of the knife can be sharpened to a cutting surface in a number of different ways. There are three main features:
  • the grind — what a cross-section looks like
  • the profile — whether the edge is straight or serrated, and straight, curved or recurved
  • away from edge — how the blade is constructed away from the edge

    Grind

Profile

Kitchen knives generally either feature a curve near the tip, as in a chef's knife, or are straight for their entire length. The edge itself may be generally smooth or "straight" edge, or it may be serrated or scalloped with "teeth". Lastly, the point may differ in shape:
  • the triangular point, most closely associated with German manufacture becoming the most common on Western knives as it is sharp, found on parers, utility, and chef's knives, as well as the Japanese knives and
  • the French point with the blade edge rising in an upwards curve and is characteristic of boning and steak knives from Thiers, Puy-de-Dôme and Laguiole, Aveyron in Occitania
  • the drop point — also called "sheep's foot" — with the tip curving down to the blade edge being common in the Osaka-style of,, and santoku knives
  • the square point is found on cleavers, along with knives of the Tokyo/Edo-style:,, and
  • the round point is usually found on long thin slicing knives, such ham and salmon slicers, as well as palette knives

    Serrations

Serrated blade knives have a wavy, scalloped, or fine-toothed saw-like blade. Serrations help when cutting things that are firm on the outside and soft on the inside ; the saw-like action breaks the surface more easily than anything except the sharpest of smooth blades. They are also particularly good on fibrous foods such as celery or cabbage. Serrated knives cut much better than plain-edge blade knives when dull, so they do not require frequent sharpening, and are sometimes used to make steak knives which do not need frequent sharpening. However, they are not readily sharpened properly by a user, requiring specialized equipment, and may never be resharpened during their useful life. Serrations are often used to improve the cutting ability of a less-expensive blade not capable of taking and keeping a sharp edge, usually having a thin, polished blade designed to minimise friction. A serrated knife is more practical for a user who is not prepared to sharpen it frequently; a well-maintained and sharpened smooth edge is keener.
Some companies have names for their own serration patterns and apply them to an entire line of knives. Examples are the Cutco Double-D edge and the Henckels Eversharp Pro series.

Indentations

Away from the edge, a knife most simply has either a rectangular or wedge-shaped cross-section, but may also have indentations, whose purpose is to reduce adhesion of the food to the blade. This is widely found in Japanese knives, and in the West is particularly found in meat carving knives, though also in knives for soft cheese, and some use for vegetables.
These indentations take many forms:
  • Granton knives have shallow curved fluted hollows or broad grooves ground into the edge that alternate on either side of the knife and extend from the edge towards the middle of the blade. This design was developed and patented in 1928 by William Grant & Sons Ltd. A similar design, kullenschliff, has oval fluting hollowed-out of one or both sides of the blade above the edge. The Granton design is normally found on meat carving knives but have recently appeared on other types of knives, especially Western variations of the Japanese santoku. The indentations require a certain thickness, so they are more frequently used on thicker, softer blades, rather than on thin, hard ones. The design of flute-sided blades is an attempt to ease the cutting and separation of meats, cheese, and vegetables through reducing the adhesion, by allowing some air between the blade and the food.
  • Urasuki is a common feature of Japanese kitchen knives. While Japanese kitchen knives initially appear as a simple chisel grind, the apparently flat side is subtly concave, to reduce adhesion, and, further, the apparent chisel cut of the edge is actually a small bevel, as otherwise the edge would be weakened by the concave area above.
  • Holes may also be found in a blade, to reduce adhesion still further. These are most found in knives for soft cheese, which is particularly sticky.