Cookbook:Knife

Knives are bladed utensils used to break down food in the kitchen.

Characteristics
Most high quality knives are manufactured from high-gauge (18/10) steel, the blade of which is either stamped or forged. A forged blade is heavier, usually hand-made, and will keep its edge, making it a popular choice for a professional chef. Forged knives tend to be more expensive, but they are seen by some as more reliable. Stamped knives are cut from sheet metal by a machine, but this process does not necessarily negate the quality. Regardless, a good knife should consist of a single piece of steel, i.e. "a full tang". In other words, the steel blade of the knife should extend through the entire length of the wood or plastic handle. A knife with a full tang is crucial for providing a balance point closer to the hand and a more durable product.

Materials
Carbon steel is an alloy of iron and carbon. The carbon steel commonly used in knives has around 1% 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. These 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 that will prevent corrosion. Unlike some grades of stainless steel, good carbon steel will take a sharp edge but is not so hard as to be difficult to sharpen.

Stainless steel is an alloy of iron, 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. 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.

Laminate 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 less hard steel, and will stay sharp longer.

Ceramic knives are very hard, made from sintered zirconium dioxide, and they retain a 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.

Selection
The most important aspect of choosing a knife is how it feels in your hand. The best way to choose a knife is simply to go try the heft of several and see what suits you best. To purchase a high quality chef's knife, try a local restaurant equipment supplier, or a well known cooking enthusiast retailer. Stay away from the cheap imitations for sale at the grocery or chain discount stores.

Storage
Knives should be stored separately from other utensils, either in a knife block, a knife tray, or with a knife guard. Never try to catch a falling knife.

Cleaning
Never leave knives in a sink full of soapy water.

Mechanical slicers
Never try to clean the circular blade of a mechanical slicer while the machine is still assembled. Always ensure that mechanical slicers and other electrical cutting equipment are disconnected from the power supply before disassembling them for cleaning.

Sharpening
Keeping a knife sharp is very important. A dull knife requires more force from the user, thereby increasing the likelihood of injury. A steel should be used to hone the edge of the blade. Honing with a steel before each use of the knife will keep the edge sharp. Occasionally a sharpening stone or high quality electric sharpener may be needed to bring a severely dulled blade back to life, followed by a few swipes on the steel.

Steel
Honing steels are used by lightly placing the near edge of the blade against the base of the steel, then sliding the blade away from yourself along the steel while moving it down—the blade moves diagonally, while the steel remains stationary. This should be done with the blade held at an angle to the steel, usually about 20°, and repeating on the opposite side at the same angle. This is repeated five to ten times per side.

It is often recommended that steeling be performed immediately before or after using a knife and can be done daily. By contrast, knives are generally sharpened much less frequently. A traditional smooth honing steel is of no use if the edge is blunt, because it removes no material; instead it fixes deformations along the edge of a sharp blade, technically known as burnishing.

Stone
Sharpening stones, water stones or whetstones are used to sharpen the edges of steel tools and implements through grinding and honing.

Sharpening stones come in a wide range of shapes, sizes, and material compositions. Stones may be flat, for working flat edges, or shaped for more complex edges. Stones are usually available in various grades, which refer to the grit size of the abrasive particles in the stone. Grit size is given as a number, which indicates the spatial density of the particles. A higher number denotes a higher density and therefore smaller particles, which leads to a finer finish of the surface of the polished object.

Chef's knife
Chef's knife is a loose term for any very large general purpose knife used mainly for chopping and slicing food, the curved blade of which allows the cook to rock the knife on the cutting board for a more precise cut. The broad and heavy blade can also be used for cutting bone instead of a cleaver. A chef's knife is generally the most used and most versatile knife in the kitchen, used for all but the finest or most specialized tasks. Selecting a chef's knife is therefore very important to comfortable and enjoyable cooking. It should be the largest size which feels comfortable to use (typically 10 inches (254 mm) for reasonably tall cooks, 8 inches (200 mm) for shorter), as a smaller knife will not be able to accomplish as many tasks with ease (chopping large vegetables, halving tortillas, pizzas, and other large foods, and so forth).

Santoku knife
Santoku knives are Japanese multipurpose knives similar to chef's knives. They tend to be slightly shorter and flatter than chef's knives, with a "drop point" and indentations on the blade to prevent food from sticking. They can be used for slicing, dicing, chopping, and more.

Paring knife
A paring knife is a smaller knife than the chef's knife, mostly used for shaping and trimming food. It is most useful for small and intricate work like removing seeds, de-veining shrimp, skinning vegetables, coring apples, and mincing vegetables. Sheep's foot paring knives and bird's beak paring knives are widely used types of paring knives. Paring knives are usually 6–10 cm (2½–4 inches) long.

Utility knife
In kitchen usage, a utility knife is between a chef's knife and paring knife in size, about 10–18 cm (4–7 inches) in length. The utility knife has declined in popularity, and is at times derided as filler for knife sets. Compared to a chef's knife, it is too short for many food items, has insufficient clearance when used at a cutting board, and is too fragile for heavier cutting tasks; compared to a paring knife, the added length offers no benefit and indeed makes control harder in these fine tasks.

Serrated knife
A serrated knife is a straight, long, slender knife with a jagged edge, often used for slicing bread. Some bread knives have an offset handle, so that the cook's knuckles don't scrape the cutting board. Bread knives are usually between 15 and 25 cm (6 and 10 inches).

Boning knife
Boning knives are very thin, sharp knives used to remove skin and bones from meat and fish. It is highly maneuverable, allowing precise separation of the flesh. It has a thin, flexible blade, usually about 12–15 cm (5–6 inches) long, that allows it to get in to small spaces. A stiff boning knife is good for beef and pork, and a flexible one is preferred for poultry and fish. Fillet knives are like very flexible boning knives that are used to fillet and prepare fish. They have blades about 15–28 cm (6–11 inches) long, allowing them to move easily along the backbone and under the skin of fish.

Carving knife
A carving knife is a knife with a blade resembling that of a chef's knife, but it's usually longer and more slender. It is useful for cutting large samples of poultry and other meats, often used in conjunction with a fork. It is much thinner than a chef's knife (particularly at the spine), enabling it to carve thinner, more precise slices.

A slicing knife serves a similar function to a carving knife, although it is generally longer and narrower. Slicers may have plain or serrated edges. Such knives often incorporate blunted or rounded tips, and feature kullenschliff or Granton edge (scalloped blades) to improve meat separation. Slicers are designed to precisely cut smaller and thinner slices of meat, and they are normally more flexible to accomplish this task. As such, many cooks find them better suited to slicing ham, roasts, fish, or barbecued beef and pork and venison.

A ham slicer is a special type of slicer, with a long blade and rounded tip, that is offered by some manufacturers. The average size of the knife is between 9 and 15 inches. They are specially tailored to cutting ham, as they are generally thinner and more flexible.

Cleaver
A meat cleaver is a large, most often rectangular knife that is used for splitting or "cleaving" meat and bone. A cleaver may be distinguished from a kitchen knife of similar shape by the fact that it has a heavy blade that is thick from the spine to quite near the edge. The edge is sharply beveled and the bevel is typically convex. The knife is designed to cut with a swift stroke without cracking, splintering, or bending the blade. Many cleavers have a hole in the end to allow them to be easily hung on a rack. Cleavers are an essential tool for any restaurant that prepares its own meat. The cleaver most often found in a home knife set is a light-duty cleaver about 6 inches (15 cm) long. Heavy cleavers with much thicker blades are often found in the trade. A "lobster splitter" is a light-duty cleaver that has the profile of a chef's knife and is used mainly for shellfish and fowl. The Chinese chef's knife is sometimes called a "Chinese cleaver", due to the rectangular blade, but it is unsuitable for cleaving, its thin blade instead designed for slicing; actual Chinese cleavers are heavier and similar to Western cleavers.

Cheese knife
Soft cheese knives are specially designed for slicing soft cheese. They generally have holes in the blade to prevent the cheese from sticking. Wire cheese cutters are also used. Hard cheese knives are specially designed for slicing hard cheese. They are sharp, so they can cut exact slices, and often have a forked tip, allowing them to be used as a serving utensil as well. A Parmesan cheese knife has a short, stubby blade. Parmesan cheese knives are specially designed for portioning very hard cheeses. They have very short, thick blades that are forced into the cheese and then used as a lever to break off smaller portions.

Butter knife
Butter knives have a dull cutting edge and are generally used for spreading. They are typically thought of more as servingware (i.e. used more as part of a table setting), to be used by diners to serve and/or spread butter or other soft spreadable foods. A modern variant that is intended for food prep is the 'sandwich spreader', a broad, flexible, almost spatula-like tool, with a rounded end and often with one serrated edge, similar to that used by pastry chefs to ice cakes. This is useful for spreading butter, mayonnaise/mustard, other similar 'spreads' or dressings, sandwich 'salad' toppings like egg salad, chicken salad, ham spread, etc., on bread.

Use
For detailed instructions on using knives in the kitchen, see the page on knife skills.