Cooking for engineers
E&T focuses on the real cutting edge of kitchen technology.
Kitchen knives come in all shapes and sizes. The variety of knife designs can sometimes be overwhelming. As you probably suspected, there is a reason for each of them to exist, but some may work better in your kitchen depending on how and what you cook.
Most kitchens operate with an all-purpose knife. In the West, this is the chef's knife. In the East, it's the Asian cleaver. More recently, the Japanese santoku has become popular as an all-purpose knife.
The chef's knife is long (usually eight to ten inches from heel to tip) and relatively wide (about two inches at the heel). It is characterised by the sweeping curve of its edge and a slight downward curve of the back of the blade as it meets the tip. This curve facilitates rocking the knife quickly back and forth to produce a fine cut or mince. Many chefs' knives are thick enough to cleave through poultry bones. This is probably the most common knife used in the Western kitchen, and if you only select one knife to use, I'd recommend one of those.
The Asian cleaver is of a completely different design. The blade, seen from the side, is usually a simple rectangle. The edge itself is straight and about six to eight inches long. The width of the blade from edge to back is often several inches.
This makes it ideal for picking up and transporting chopped vegetables and meat. Its blade is often used for unlikely purposes: the side for smashing garlic and ginger, the back for tenderising meat.
The santoku, a popular Japanese knife, is like a chef's knife melded with a cleaver. Instead of the shallow curve, its back abruptly curves down to meet the edge near the tip of the knife, thus forming a more rectangular shape. Santoku is typically six inches in length and about two inches from edge to back (so it will fit in a standard knife block). It lacks the heft and size of the Asian cleaver, so its functions are more akin to a chef's knife. Because of its reduced length (resulting in finer control) and exotic look, many cooks favour the santoku over the latter and use it as their all-purpose knife.
Even though the all-purpose knife does the majority of the work in the kitchen, speciality knives have their place too. Their choice depends on the food you prepare. A paring knife is typically the speciality knife that gets reached for the most. With a blade of about four inches, it works well with small objects that require precision: paring apples, seeding chilli peppers, butterflying shrimp or simply opening the plastic wrap on a supermarket packaged steak - a task that would be cumbersome to achieve with a chef's knife. The paring knife looks like a chef's knife that has undergone a shrink ray.
A boning (or fillet) knife is typically six inches long, narrow (about half an inch from edge to back), and thin (usually thin enough to make the blade flexible). The blade is designed to be easily manoeuvered while removing meat from bones. Even if you don't bone chickens on a regular basis, the boning knife can be used where a thin flexible blade makes things easier - for example, for removing melon meat from the rind after it's been sectioned.
A carving knife is a long knife (usually longer than eight inches) with a moderate width blade (about one inch). The long blade allows roasts to be sliced with one long stroke providing an even cut throughout. It is usually constructed of thinner metal than of a chef's knife, so it has a better chance of cutting through the roast without getting stuck and tearing the meat.
All the knives we've discussed so far have been plain-edged (also known as smooth- edged or non-serrated). Plain-edged knives cut best when a slicing motion (dragging the edge of the blade across the item to be cut) is employed, but they also cut well (if sharp) when chopping or simply pushing or pressing through the ingredients. Serrated knives have uniform bits cut out of the edge. The interior edges and points of the serrations are sharpened. They only cut well when a slicing motion is used.
The bread knife is probably the all-purpose knife of the serrated world. Around eight inches long, it is capable of cutting large objects like bread. The serrations provide grip for the knife to cut (or saw) through the hard items.
Serrated knives are also useful for cutting products with a tough exterior and a soft interior. The classic example is a tomato which has a relatively tough skin but is also slick and often slippery. The interior of the tomato is extremely soft and too much pressure (like pressing a plain knife straight down on it) will cause it to burst and squirt out. Using a practiced slicing motion with a very sharp plain knife results in perfect cuts, but a serrated knife, like the bread one, helps grip the tomato and makes it easy to produce straight, even cuts.
There are also utility knives (longer versions of the paring knife), sandwich knives (shorter versions of the bread knife), steak knives (knives used for cutting at the dining table) and meat cleavers (broad-bladed knives with a lot of heft designed to chop through solid bone). Unless you have a specific need, you'll probably find that a combination of two or three of the knives described above will work perfectly with your style of cooking.