Cooking Basics
Types of Cooking
Since physics is no longer universally taught in schools as it was when I was a child, I think that it may be useful to discuss the different methods of heat transference before we look at cooking itself. In the 1960's there were no microwave ovens and so the three methods of heat transference were convection, conduction and radiation.
CONVECTION - This is a cooking method that results from the movement of hot air around the item to be cooked. It is an indirect method of heat transfer because there is no direct contact between the heat source and the food being cooked. Usually, convection ovens will have a fan that aids in circulating the heated air although, provided the dynamics of air flow are sufficient, this is not a pre-requisite. Most of the high-end gas ranges are convection ovens.
CONDUCTION - This is really the most basic of all heat transference modes and all cooking, even microwave, involves this method to some degree. This is, in its simplest form, where heat is transferred by direct contact with something that is hotter than the item being cooked. Even microwaves typically only penetrate an inch or so into foods, therefore the balance of cooking must be achieved by another method.
RADIATION - Radiant heat is not nearly as dangerous as its name would lead us to believe. This is perhaps the most direct type of heat and thus, it is also the most instantaneous although it is also the least useful and least effective in the kitchen. This is usually regarded as a ?dry heat?.
To illustrate these three types of heat and how they work, let?s imagine someone basking in the sun on the beach. The heat coming directly from the sun is probably the best example of radiant heat that we could expect to find. One reason that most people prefer a towel to lie on is because the sand, heated by the sun, will immediately transfer heat to your body on contact by conduction. On a really hot day, you will almost invariably find a breeze on the beach close to the water. This is because of a convection current set up by the hot air rising from the heated sand being replaced by the cooler air coming off the water which will always be cooler than the sand.
MICROWAVES - Microwave heating is really a hybrid type of heat but is most directly related to radiant heat. The microwaves work on a molecular level, imparting energy directly to the molecules with which they come into contact. These molecules begin to vibrate and touch other molecules and transferring kinetic energy. From this point on, heating is done by conduction. Even though production of microwaves stops the instant you open the door, the molecules are still vibrating and just like your car after taking the foot off the gas, they will ?freewheel? for a while before coming to a standstill. Hence the need for ?standing time?.
The above may all sound rather esoteric but it really helps to understand it before selecting the appropriate tools, cookware and heating methods to cook foods without resort to recipes and cookbooks. It also helps to explain things you knew but didn?t necessarily understand such as not opening the oven door whilst a cake is baking etc.
