Chef's knife

In cooking, a chef's knife, also known as a French knife, is a cutting tool used in preparing food. It is the kitchen knife that most cooks use most of the time.

A chef's knife generally has an eight-inch (20 cm) blade, although individual models range from six to 12 inches (15 to 30 cm) in length. A Western-style chef's knife typically has a pointed end. In the equivalent Japanese knife, called a santoku (literally: "three uses": slicing, dicing, & mincing — but a better translation might be "all-purpose"), the blade's spine drops more sharply to meet the cutting edge.

Physical description

Materials

The blade of a chef's knife is made from one of these materials:

Carbon steel: An alloy of iron and approximately 1% carbon. Both Easier to sharpen than stainless, and holds an edge longer, but is vulnerable to rust and stains. Some professional cooks swear by knives of carbon steel because of their sharpness. Over time, a carbon-steel knife can acquire a dark patina, and carbon steel (unlike stainless steels) rusts if not cared for properly. Some chefs find that the extra sharpness is not worth keeping the steel clean & polished; others find that carbon steel's sharpness qualities outweigh the additional maintenance requirements.

Stainless steel: An alloy of iron, approximately 10-15% chromium, possibly nickel, and molybdenum, with only a small amount of carbon. Lower grades of stainless steel are not able to take as sharp an edge as carbon steel, but are resistant to corrosion, do not taint food and are inexpensive. Higher grade and 'exotic' stainless steels (mostly from Japan - as used by Global, Kasumi and others) are extremely sharp with excellent edge retention, and equal or out perform carbon steel blades but they are expensive.

Laminated. As noted above, all materials used in blades represent various compromises. A laminated knife tries to use the best of each material by creating a layered sandwich of different materials -- for instances, using a softer-but-tough steel as the backing material, and a sharper/harder - but more brittle - steel as the edge material.

Ceramic blades hold an edge the longest of all, chip easily and will break if dropped. They also require special equipment and expertise to resharpen. They are sintered to shape with zirconium oxide powder. They are chemically nonreactive, so will not discolor or change the taste of food.

The handle may be made from:

Wood
Plastic
Steel

Or any of a number of synthetic/composite materials.

The edge may be ground in different ways:

V-shape
Beveled edge.
Hollow-ground.

Manufacturing

For a steel knife, there are two ways to fashion the blade.

Hot-forged: A hot-forged blade is made in an intricate, multi-step process, often by skilled manual labor. A chunk of steel is heated to a high temperature, and beaten to temper the steel. Forging refines the grain of the steel, which increases the metal's touhgness. After forging, the blade is ground down and sharpened. Forged knives are usually also full-tang, meaning the metal in the knife runs from the tip of the knifepoint to the far end of the handle.
Stamped: A stamped blade is cut to shape directly from cold rolled steel and then ground down and sharpened. Stamped blades lack the benefits of the toughness brought by forging, but they are cheaper to produce. As the quality of rolled steel improves, they may approach the quality of hot-forged blades.

Buying a chef's knife

Someone in the market for a chef's knife will make a choice based on price, the cost of maintenance, and how the knife feels in the hand (often called the balance). Considered qualities may include cost, maintenance, edge, corrosion resistance and balance. The appearance of the knife is often taken into account as well, especially when purchased for domestic use.

Using a chef's knife

Technique for the use of a chef's knife is an individual preference. Nevertheless, professional chefs commonly follow certain practices.

Perhaps the most basic difference in technique has to do with how the cook physically places his or her hand on the knife. Some prefer a grip around only the handle, with all four fingers and the thumb gathered underneath as in a clenched fist. Others prefer a grip on the blade itself, with the thumb and the index finger grasping the blade just to the front of the finger guard and the middle finger placed just opposite, on the handle side of the finger guard below the bolster. The size and shape of the particular knife, and the job it is being used to do, are also important considerations.

Actually applying a chef's knife to different kinds of food in an effective way is a matter of demonstration and experience. For example, a good chef's knife can be used to dice both tomatoes and onions, but the characteristics of each vegetable require different motions with the knife which may not be immediately obvious without instruction. Some techniques seen on fast-paced cooking shows should likely not be attempted by anyone without professional experience.

Regardless of how the knife is being used, the cook should be mindful of their own comfort, safety and confidence when using a chef's knife: a knife in hurried hands can cause a nasty cut. A good motto is "Know where the sharp part is pointing," the sharp part being the entire edge from point to heel. Knowing how to hold the food that is being cut is equally as important as knowing how to hold the knife, as the hand not holding the knife is in a subtly obvious way the most likely to be cut. For example, when holding large items such as a head of lettuce, the thumb of the hand not holding the knife should never be tucked underneath.

Professional chefs may develop very close affiliations with their knives and may not allow others to use them under any circumstances. Knife preference, in terms of length, weight, brand, and nearly any other criteria, is often hotly debated in restaurant kitchens, but even cooks at home should carefully consider a potential knife. A good chef's knife can be a family hierloom as treasured as a cast-iron pan.

Extensive, ongoing use of a chef's knife may lead to a hardening at the base of the index finger sometimes called a "knife callous."

References

Lee, Matt and Lee, Ted (December 15, 2004). When a Knife Is the Gleam in a Cook's Eye. New York Times.
Cooking For Engineers - Examination of Parts of a Chef's Knife and what to look for when buying a kitchen knife.