Construction
Material
Carbon steel is an alloy of iron and carbon, often including other alloys 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 most stainless steels, but is vulnerable to rust and stains. The blades must be cleaned, dried, and lubricated after each use and new carbon-steel knives may impart a metallic or "iron" flavor to acidic foods, though over time, the steel will acquire a patina of oxidation which will prevent corrosion.
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 out of 420 stainless, a high-chromium, low-end stainless steel alloy often used in flatware. Most consumer grades of low-carbon stainless are considerably softer than carbon steel and more expensive grades of stainless, and must be more frequently sharpened though most are highly resistant to corrosion. The thin, flexible, shiny blades common in cheap kitchen knives are typically made of low-carbon, inexpensive stainless alloys. They are difficult to sharpen, so they are often made with serrations, which slows dulling and enables them to cut adequately when they do become dull.
High carbon stainless steel normally refers to higher-grade, stainless steel alloys with a certain amount of carbon, and is intended to combine the best attributes of carbon steel and ordinary stainless steel. High carbon stainless steel blades do not discolor or stain, and maintain a sharp edge. Most of these 'high-carbon' stainless blades also feature higher quality 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. Examples of such steels include 440-C, AUS-8, AUS-10, ATS-34, ATS-55, vg-10, 154cm and many others.
Laminated blades attempt to use the best of multiple materials by creating a layered sandwich of different steel alloys. By alternating layers of brittle and hard steel the blade combines the attributes of both metals though it is neither as stiff as the brittle steel or as flexible as the hard steel in isolation. Many higher-quality knives are made this way. A laminated blade's edge can often be made harder than an ordinary stainless steel knife, in turn facilitating a more acute grind on the cutting blade and increasing the knife's cutting abilities.
Titanium is lighter and less wear resistant, but because it does not get hard, it does not take a very good edge. However it is more flexible than steel. Titanium does not impart any flavor to food. It is typically expensive and not well suited to cutlery, used only as a buzz word.
Ceramic knives are very hard, light, do not impart any taste to food and do not corrode but require special tools for sharpening. Ceramic blades are also very brittle, and will chip if struck against hard objects or sharpened improperly. They may snap if used to pry or lever foods or other materials apart.
Plastic blades are not very sharp and are mainly used to cut through vegetables without causing discoloration. They are not sharp enough to cut deeply into flesh, but can cut or scratch skin.
Blade
Steel blades can be manufactured either by being forged or stamped.
Forged blades are made in an intricate, multi-step process, often by skilled manual labor. A chunk of solid or powdered 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 quenchant, and tempered to the desired hardness. After forging and heat treating, the blade is polished and sharpened. Forged blades are typically thicker and heavier than stamped blades, an advantage in some situations.
Stamped blades are cut to shape directly from cold rolled steel, heat-treated for strength, then ground, polished, and sharpened. Though they are not preferred by most professional chefs, several popular knife brands, such as Global, do use stamped and heat-treated blades in their premium knives. Stamped blades can often, but not always, be identified by the absence of a bolster.
Edge
For more details on this topic, see Grind.
The edge of the knife can be sharpened to a cutting surface in a number of different ways.
Flat ground blades have a profile that tapers from the thick spine to the sharp edge in a straight or convex line. Seen in cross section, the blade would form a long, thin triangle, or where the taper does not extend to the back of the blade, a long thin rectangle with one peaked side. They are heavier and tougher than a hollow ground knife.
Hollow ground blades have concave, beveled edges that are ground starting midway down the blade, instead of at the spine. The resulting blade has a thinner edge, so it may have better cutting ability, but it is lighter and less durable.
Serrated blade knives have a wavy, scalloped or saw-like blade. Serrations make knives ideal for cutting things that are hard on the outside and soft on the inside (such as bread or tomatoes) that might otherwise be ruined by a slightly dull knife with a plain, flat-ground edge. They are also particularly good on fibrous foods like celery or cabbage. Serrated knives cut much better than plain edge blade knives when dull, so they may go longer without sharpening (some serrated blades are claimed never to need sharpening.) However, they require specialized equipment and a different technique in order to resharpen them. Further, serrations are often used to improve the cutting ability of a less-expensive, soft stainless alloy blade, (usually incorporating an extremely thin blade design to reduce friction). For this reason, some professional chefs recommend buying at least a moderately-priced serrated knife made of high-carbon stainless, as these knives will inevitably dull and have to be replaced or resharpened. Some companies have names for their own serration patterns and apply them to an entire line of knives. Examples are Cutco's Double-D edge and Henckel's Eversharp Pro series.
Granton edges 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 edge was designed and patented in 1928 by Granton Ragg Ltd. A similar design, kullenschliff (kulle is Swedish for hill; schliff means sharpened in German), has oval scallops (kullar) hollowed-out of one or both sides of the blade above the edge. These are normally found on meat carving knives but have recently appeared on other types of knives, especially Western variations of the Japanese santoku. The design of scallop-sided blades is an attempt to ease the cutting and separation of meats, cheese, and vegetables.
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. Some people argue that ordinary varnished wood handles can harbor more microorganisms as the varnish layer wears off, thus requiring resealing or revarnishing to seal the wood's pores.
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 knives are made from laminated wood composites impregnated with plastic resin. Pakkawood and Staminawood are commonly encountered composite wood handles. They 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. 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, 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.
Nomenclature
A Point: The very end of the knife, which is used for piercing
B Tip: The first third of the blade (approximately), which is used for small or delicate work
C Edge: The cutting surface of the knife, which extends from the point to the heel. The edge may be beveled or symmetric.
D Heel: The rear part of the blade, used for cutting activities that require more force
E Spine: The top, thicker portion of the blade, which adds weight and strength
F Bolster The thick metal portion joining the handle and the blade, which adds weight and balance and keeps the cook's hand from slipping
G Finger Guard: The portion of the bolster that keeps the cook's hand from slipping onto the blade
H Return: The point where the heel meets the bolster
J Tang: The portion of the metal blade that extends into the handle, giving the knife stability and extra weight
K Scales: The two portions of handle material (wood, plastic, composite, etc) that are attached to either side of the tang
L Rivets: The metal pins (usually 3) that hold the scales to the tang
M Handle Guard: The lip below the butt of the handle, which gives the knife a better grip and prevents slipping
N Butt: The terminal end of the handle
Types
General
Different types of kitchen knives
Chef's knife
Also known as a cook's knife or French knife even though the knife style originates as the German cook's knife , the chef's knife is an all-purpose knife that is curved to allow the cook to rock the knife on the cutting board for a more precise cut. The broad and heavy blade also serves for chopping bone instead of the cleaver making this knife the all purpose heavy knife for food preparation. Chef's knives are most commonly available between 15 cm and 30 cm (6 and 12 inches), though 20 cm (8 inches) is the most common size.
Bread knife
Bread knives are a type of serrated knife that is usually between 15 cm and 25 cm (6 and 10 inches), with 20 cm (8 inches) being a common length. The serrations on the blade make it ideal for cutting bread and other foods with a hard surface and soft interior. An offset serrated knife uses an offset handle to ensure the cook's knuckles will not touch the cutting surface when the blade has cut all of the way through the food.
Paring
A paring knife is a small knife with a plain edge blade that is ideal for peeling and other small or intricate work (such as de-veining a shrimp, removing the seeds from a jalapeño, or cutting small garnishes). It is designed to be an all-purpose knife, similar to a chef's knife, except smaller. Paring knives are usually between 6 and 10 cm (2½ and 4 inches) long.
Utility |