Basic Principles Of Heat

!±8± Basic Principles Of Heat

You'll notice that frequently the physical dimensions or power requirements are listed for particular kinds of appliances. You certainly do not have to memorize these figures; rather, the idea is to acquaint you using the numerous options available from manufacturers and to prompt you to think about size and utility usage when outfitting your kitchen. Before you learn about the kinds of ranges and ovens available, it would be helpful to realize a few cooking-related terms. This is info you may have already learned in your culinary training; however, it is important enough to summarize briefly the cooking processes that are central to each kitchen. Conduction is the simplest form of heat transfer. Heat moves directly from one item to an additional when they're brought into direct contact with every other. Poaching, boiling, and simmering are all examples of conduction cooking. Induction cooking creates heat when an electromagnetic field is created between stovetop and pan, creating currents which are converted to heat by the natural resistance of the metal pan.

This electromagnetic field can be achieved only if the pan is made of ferrous metal, such as cast iron or stainless steel; nonmagnetic copper and aluminum pans will not work. Induction cooking surfaces don't become warm, because the heat is transferred directly into the pan. When the pan is removed from the heat source, the induction process ends automatically, with no residual heat. Convection happens when heat is distributed by moving air, steam, or liquid. The simplest form of convection occurs when you stir a thick sauce, for instance, to circulate it and heat it thoroughly within the pan. Convection cooking was discovered when U.S. Navy researchers placed fans in standard oven compartments to see if foods might be cooked a lot more rapidly when warm air was blown around it. They discovered that, indeed, the convection process cooked food faster and more evenly, no matter where within the oven the foods was placed.

Why? Simply because the warm air reduces the cool "boundary layer" at the surface from the foods, allowing the heat to penetrate the food faster. Radiation happens when waves of energy hit the food and cause a heating reaction. Two kinds of radiation are used within the kitchen: infrared and microwave. In a broiler, the heating element becomes warm sufficient to release infrared radiation, which cooks foods really quickly. The other type, the microwave oven, used to be known as magnetron cooking and was developed during World War II. U.S. airmen noticed they could keep their coffee warm by setting it near the plane's radar equipment box. The short, electromagnetic waves emitted at the speed of light react to moisture, which is found in almost all foods. The moisture molecules in the coffee cup create friction as they try to align themselves using the microwaves, and friction creates heat. These days, this easy principle has discovered its way into almost every American house.