Marrying Convection and Microwave Ovens
Microwave ovens cook or heat foods using dielectric or electronic heating. They emit radio waves with frequencies of 2.5 gigahertz that pass through and are absorbed by the food inside the oven. These agitate the atoms inside the food thus creating heat and cooking or warming it at speeds beyond those of their conventional cousins. And since neither glass, ceramics, nor plaster can absorb the radio waves, only the food is heated.
Convection ovens, on the other hand, make use of conventional heating elements that are often made of Nichrome, which is a combination of nickel (80%) and chromium (20%). By resisting electric current flowing into them, the elements themselves are heated transforming themselves into glowing rods. All convection ovens have at least two elements, one at the top and another at the bottom of the oven cavity. However, what differentiates them from conventional ovens is their internal fan or fans designed to circulate and distribute heated air within the oven. With this feature, cooking is quickened, although not as fast as the microwaves. Food is more evenly cooked with neither burnt nor undercooked portions, with their surface browned thus trapping the moisture inside.
Some people have reservations about the use of radio waves for cooking. Indeed, the slang for microwave cooking is “to nuke the food”. People who are often hard-pressed for time, however, find microwave ovens a blessing. They can cook anything, as there seems to be microwavable versions of almost every food, from popcorn to turkey.
The downside, though, is that they cannot brown or bake foods. There is also the possibility that because the waves bounce off the walls of the oven in a set pattern, some cold spots may remain. This may result in an area of the food being undercooked.
These issues are easily addressed by mating convection oven features with the microwave oven. The perceived weaknesses of the latter are precisely the strengths of the former, thus it is not surprising that there are already a number of manufacturers marketing convection microwave ovens.