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The principles of microwave cooking, Food characteristics, Microwave techniques – Emerson MW8117W User Manual

Page 18: Cooking guide, Reflection, Transmission, Absorption

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COOKING GUIDE

THE PRINCIPLES OF MICROWAVE COOKING

Microwaves are a form of high frequency radio waves similar to those used by a radio including AM, FM and CB.

Electricity is converted into microwave

energy

by the magnetron tube. From the magnetron tube, microwave

energy is transmitted to the oven where it is reflected, transmitted and absorbed by the food.

Reflection

Microwaves are reflected by metal just as a ball is bounced off of a wall. For this reason, metal utensils are not

suitable for use in the microwave. A combination of stationary interior walls and a rotating metal turntable or stirrer fan

helps assure that the microwaves are well distributed within the oven cavity to produce even cooking.

Transmission

Microwaves pass through some materials such as paper, glass and plastic much like sunlight shining through a

window. Because these substances do not absorb or reflect the microwave energy, they are ideal materials for

microwave oven cooking containers.

Absorption

During cooking, microwaves will be absorbed by food. They penetrate to a depth of about 3/4 to 1 1/2 inches.

Microwave energy activates the molecules in the food (especially water, fat and sugar), and heat is produced. It you

vigorously rub your hands together, you will feel heat produced by friction. The internal cooking of larger foods is done

by conduction as the heat which is produced by friction is conducted to the middle of the food. Foods also continue to

cook by conduction during standing time.

FOOD CHARACTERISTICS

Quantity:

The amount of food placed in a microwave oven has a direct effect on the cooking time. Small amounts of food

or liquid require less cooking time than larger amounts of the same substance. As quantity increases, concentration

decreases.

Size:

Small pieces cook faster than large ones. To speed cooking, out pieces smaller than two inches (5 cm), so microwaves

can penetrate to the middle from all sides. Pieces which are similar in size and shape cook more evenly.

Shape: Many foods are uneven, like a chicken, ribs or broccoli. The thin parts will cook faster than the thick parts, while

uniformly thick foods cook evenly. To compensate for irregular shapes, place thin pieces toward the center of the dish

and thicker pieces toward the edge of the dish.

Starting Temperature:

Frozen or refrigerated foods take longer to cook than foods at room temperature.

Bone and Fat: Because bones conduct heat, the side of the meat the bone is on will cook first, while boneless cuts cook

slower but more evenly. Fat attracts microwaves. The middle of these foods are cooked by heat conduction.

Moisture Content:

Microwaves are attracted by moisture. Naturally moist foods absorb microwaves better than dry ones.

Add a minimum of liquid to moist foods, as excess water slows cooking.

Density: The density of food determines how easily the microwaves can penetrate and how quickly it will cook. Porous

foods, like chopped beef or mashed potatoes, microwave faster than dense ones like steak or whole potatoes.

Piercing: Steam builds up pressure in foods which are tightly covered by a skin or membrane. Pierce potatoes, egg yolks

and chicken livers to prevent bursting.

MICROWAVE TECHNIQUES

stirring: Stir foods from outside to center of dish once or twice during cooking to equalize heat and speed microwaving.

Foods will not burn or stick, so there’s no need to stir constantly as you do in conventional cooking.

Arrangement:

Arrange foods with thin or delicate ends, like drumsticks or asparagus spears, with the thick or tougher

portions to the outside of the dish. The parts which need more cooking will receive more energy, so food will microwave

evenly.

Spacing: Individual foods, such as baked potatoes and cupcakes will cook more evenly if placed in the oven an equal

distance apart. When possible, arrange foods in a circular pattern. Similarly, when placing foods in a baking dish, arrange

around the outside of the dish, not lined up next to each other. Food should not be stacked on top of each other.

Rearrangement: Rearrange overlapping areas, like tails of long fish fillets, from top to bottom, and closely packed pieces, like

meatballs, from the outside to the center of the dish.

Standing Time:

Standing time is especially important in microwave cooking. Microwave energy creates heat in the outer

layers of the food. As a result of normal conduction, the food continues to cook for a few minutes after removal from the oven.

Letting roasts, large whole vegetables, casseroles and cakes stand to finish cooking allows the middles to cook completely

without overcooking, drying or toughening the outsides.

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