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A kitchen knife is any knife that is intended to be used in food preparation. While much of this work can be accomplished with a few general-purpose knives – notably a large chef's knife, a tough cleaver, a small paring knife and some sort of serrated blade (such as a bread knife or serrated utility knife) – there are also many specialized knives that are designed for specific tasks. Kitchen knives can be made from several different materials.

Construction

Material

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• Carbon steel is an alloy of iron and carbon, often including other elements such as vanadium and manganese. Carbon steel commonly used in knives has around 1.0% carbon (ex. AISI 1095), 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.^[1]

• Laminated 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 (laminated) and protected between layers of the tougher steel. The hard steel forms the edge of the knife; it will take a more acute grind than a softer steel, and will stay sharp longer.

• Titanium is lighter and more corrosion-resistant, but not harder than steel. However it is more flexible than steel. Titanium does not impart any flavour to food. It is typically expensive and not well suited to cutlery.

• Ceramic knives are very hard, made from sintered zirconium dioxide, and retain their sharp edge for a long time. They are light in weight, do not impart any taste to food and do not corrode. Suitable for slicing fruit, vegetables and boneless meat. Ceramic knives are best used as a specialist kitchen utensil. Recent manufacturing improvements have made them less brittle. Because of their hardness and brittle edges, sharpening requires special techniques.

• Plastic blades are usually not very sharp and are mainly used to cut through vegetables without causing discolouration. They are not sharp enough to cut deeply into flesh, but can cut or scratch skin.

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 chunk of steel alloy is heated to a high temperature, and pounded while hot to form it. The blade is then heated above critical temperature (which varies between alloys), 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 (a "straight" or "clean" edge), or may be serrated or scalloped (have "teeth") in some way. Lastly, the point may differ in shape: most common is a sharp, triangular point (as in photo), as in a chef's knife or paring knife, though the French point (also called "Sheep's foot") is common in santoku, and a round point is sometimes found on long slicing knives.

• Serrated blade knives have a wavy, scalloped or saw-like blade. Serrations help when cutting things that are hard on the outside and soft on the inside (such as bread or tomatoes); the saw-like action breaks the surface more easily than anything except the very sharpest smooth blade. 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 (some serrated blades are claimed never to need 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 (saber grind vs. flat grind), 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 semi-circular scallops ground into the edge that alternate on either side of the knife and extend from the edge to the middle of the blade. This design was developed and patented in 1928 by William Grant & Sons Ltd.^{[citation needed]} A similar design, kullenschliff (kulle is Swedish for hill (or -more likely- a misspelling of the German word "Kuhle" meaning "hollow" or "deepening"); schliff meaning "cut" or grind in German), has oval scallops (kuhlen) 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 scallop-sided blades is an attempt to ease the cutting and separation of meats, cheese, and vegetables.

• Urasuki is a common feature of Japanese kitchen knives.^[2] While Japanese kitchen knives initially appear as a simple chisel grind (flat on the side facing the food, angled on the other), 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 soft and sticky.

Sharpening

The edge of a knife gradually loses its sharpness, which can be restored by sharpening. For many types of knives (e.g., butter knives) this is not relevant. Knives with smooth edges can be sharpened by the user; knives with any form of serrated edge should ideally be sharpened with specialist equipment, although the useful life of a serrated knife can be extended by simple sharpeners, even if they damage the edge.

Handle

The handles of kitchen knives can be made from a number of different materials, each of which has advantages and disadvantages.

• Wood handles provide good grip, and most people consider them to be the most attractive. They are, however, slightly more difficult to care for as they must be cleaned more thoroughly and occasionally treated with mineral oil. Most wood handles, especially those of ordinary varnished hardwood, do not resist water well, and will crack or warp with prolonged exposure to water. They should be hand-washed for that reason.
• Plastic handles are more easily cared for than wooden handles and do not absorb microorganisms. However, plastics may also be less resistant to ultraviolet damage and may become brittle over time, resulting in cracking. Some plastics are also slippery in the hand. The material is lighter than most other materials, which may result in a knife that is off-balance or too light for some tastes.
• Composite "pakka wood" knives are made from laminated wood composites impregnated with plastic resin. Composite handles are considered by many chefs to be the best choice because they are as easy to care for and as sanitary as plastic, they have the appearance, weight, and grip of hardwood, and are more durable than either.^{[citation needed]} They often have a laminated, polished appearance, and may have intense or varied coloring.
• Stainless steel handles are the most durable of all handles, as well as the most sanitary. Many argue,^[who?] however, that they are very slippery in the hand, especially when wet. To counter this, many premium knife makers make handles with ridges, bumps, or indentations to provide extra grip. One disadvantage of some all-metal handles is that knife weight usually goes up considerably, affecting the knife's balance and increasing hand and wrist fatigue. Knife manufacturers, most notably Japan's Global, have begun addressing this issue by producing hollow-handled knives.

Nomenclature