Food Preparations - Microwave

A microwave oven, or simply a microwave, is a kitchen appliance that cooks or heats food by dielectric heating. This is accomplished by using microwave radiation to heat polarized molecules within the food. This excitation is fairly uniform, leading to food being more evenly heated throughout (except in dense objects) than generally occurs in other cooking techniques.

Basic microwave ovens heat foods quickly and efficiently, but do not brown or bake food in the way conventional ovens do. This makes them unsuitable for cooking certain foods, or to achieve certain culinary effects. Additional kinds of heat sources can be added to microwave packaging, or into combination microwave ovens, to add these additional effects.
A variant of the conventional microwave is the convection microwave. A convection microwave oven is a combination of a standard microwave and a convection oven. It allows food to be cooked quickly, yet come out browned or crisped, as from a convection oven. Convection microwaves are more expensive than conventional microwave ovens. Some convection microwaves—those with exposed heating elements—can produce smoke and burning odors as food spatter from previous microwave-only use is burned off the heating elements.

More recently, some manufacturers have added high power quartz halogen bulbs to their convection microwave models, marketing them under names such as "Speedcook", "Advantium" and "Optimawave" to emphasize their ability to cook food rapidly and with good browning. The bulbs heat the food's surface with infrared (IR) radiation, browning surfaces as in a conventional oven. The food browns while also being heated by the microwave radiation and heated through conduction through contact with heated air. The IR energy which is delivered to the outer surface of food by the lamps is sufficient to initiate browning caramelization in foods primarily made up of carbohydrates and Maillard reactions in foods primarily made up of protein. These reactions in food produce a texture and taste similar to that typically expected of conventional oven cooking rather than the bland boiled and steamed taste that microwave-only cooking tends to create.

In order to aid browning, sometimes an accessory browning tray is used, usually composed of glass or porcelain. It makes food crisp by oxidising the top layer until it turns brown. Ordinary plastic cookware is unsuitable for this purpose because it could melt.

Frozen dinners, pies, and microwave popcorn bags often contain a thin scepter made from aluminium film in the packaging or included on a small paper tray. The metal film absorbs microwave energy efficiently and consequently becomes extremely hot and radiates in the infrared, concentrating the heating of oil for popcorn or even browning surfaces of frozen foods. Heating packages or trays containing scepters are designed for single use and are discarded as waste.

Types/Sizes

Portable or Desktop

    This is the smallest size of microwave oven in the market. The common models measure around 28 centimetres (11 in) tall, 38 centimetres (15 in) wide and 25 centimetres (9.8 in) deep. Some of the experimental models on trial are as small as 19 centimetres (7.5 in) tall, 6 centimetres (2.4 in) wide and 15 centimetres (5.9 in) deep. Some of these use 12 V DC power supplies.

Compact

    A compact microwave oven, also called small, is the smallest type typically available. Compacts are the most popular size of microwave oven, dominating the market. A typical model is no more than 50 centimetres (20 in) wide, 35 centimetres (14 in) deep and 30 centimetres (12 in) tall. These ovens are rated between 500 and 1000 watts and have less than 28 litres (0.99 cu ft) in capacity. These ovens are primarily used for reheating food and making microwave meals and popcorn. The largest models can accommodate 2 litres (1.8 imp qt) round casserole dishes and are suitable for light cooking. These ovens are not made to cook large amounts of food. Typically these models cost less than USD$100 (around £50).

Medium-capacity

    These models' heights and depths are only marginally larger than compacts, but they are typically more than 50 centimetres (20 in) wide. Their interiors are typically between 30 and 45 litres (1.1 and 1.6 cu ft), and power ratings are 1000–1500 W. These are the common "family sized" microwave ovens. They tend to have a few more "auto-cook" features, and some incorporate grills or even conventional-oven heating elements.
Large-capacity
    These are designed for cooking large meals. Large-capacity ovens can handle 25 by 35 centimetres (9.8 by 14 in) casserole dishes and cook tall items like roasts or turkey breasts, with a large number of "auto-cook" and precise temperature control measures. Large-capacity ovens normally use over 2000 W and have over 60 litres (2.1 cu ft) of capacity. These ovens are normally well over 50 centimetres (20 in) wide, as much as 50 centimetres (20 in) deep, and at least 30 centimetres (12 in) high.

Built-in

    These are built into cabinetry and are typically more expensive than similar sized counter top models. Some models include exhaust fans to allow installation above cook tops.