Generality
The microwave oven - or more simply “microwave” - is a kitchen appliance that heats and cooks food through exposure to electromagnetic radiation.
Microwave ovens cook food quickly and efficiently, since they exert a completely uniform excitation (especially in reference to other methods) on all foods with a high water content (less on thicker ones with low humidity).
The first microwave oven was invented after the Second World War by Percy Spencer, who used the radar technology developed by the American nation during the conflict; not surprisingly, the first name of the microwave oven was "Radarange".
The "Raytheon" (US defense company) then granted the license to use its patents for domestic use, introduced by W. J. Tappan in the year 1955; however, the tools were still too large and above all expensive to be applied in home use. In 1967 the "Amana Corporation" introduced the first "microwave worktop" and its use quickly spread to commercial and home kitchens. Worldwide.
Today, microwave ovens are widely used, especially for heating already cooked food and for cooking a particular variety of foods. They are also useful for the rapid melting of certain otherwise more demanding ingredients, such as butter and chocolate to be melted (traditionally worked in a bain-marie).
how does the microwave oven work?
Some of the molecules that make up food - in particular those of water, but also lipids and carbohydrates - tend to line up in the direction of the electric field that may be present, a bit "like the needle of a compass tends to align itself with the magnetic field. This characteristic is due to the fact that these molecules have an "end with a positive electric charge and another" with a negative charge, for this reason they are called polar or polarized molecules or electric dipoles.
Inside a microwave oven an electric field is generated that reverses its direction a few billion times per second. As a result, the polar molecules of food change their orientation several billion times per second; this movement generates a continuous collision. between adjacent molecules, with reciprocal transfer of motion, hence the diffused heat that allows food to be cooked up to a few centimeters deep.
Microwaves heat water more efficiently, but to a lesser extent also fats, sugars and ice.
Unlike conventional ovens, microwave ovens usually do not reach temperatures sufficient to significantly trigger Maillard reactions (see also: cooking sugars, cooking fats, cooking proteins), therefore - for example - they are not suitable for the browning of toast and croutons. Some exceptions occur in cases where the microwave oven is used to heat doughs rich in oil or other very fatty products (such as lard or bacon), which reach temperatures much higher than those of water. , there are accessories with thin metal coatings which, becoming rather hot, can toast the foods that are in contact with them.
Precisely due to the fact that the temperatures necessary for frying, gratinating and roasting are rarely reached, microwave ovens play a rather limited role in the professional kitchen. However, the microwave technology can be integrated with other types of cooking (eg pre-cooking intended for "roasting); or, the ovens themselves can be manufactured by integrating with other heat production systems (such as the grill); in this "last case we talk about combi ovens. In addition, certain more modern instruments can be part of the so-called “over-the-range” units, with built-in hoods.
