11
Microwave energy has been used in this country to cook and reheat food since early experiments with
RADAR in World War II. Microwaves are present in the atmosphere all the time, both naturally and
from manmade sources.
Manmade sources include radar, radio, television, telecommunication links and mobile phones.
Microwaving Principles
The microwaves cause the water molecules to vibrate which causes FRICTION, i.e. HEAT. This heat
then cooks the food. Microwaves are also attracted to fat and sugar particles, and foods high in these
will cook more quickly. Microwaves can only penetrate to a depth of 1
1
⁄
2
-2 inches (4-5 cm) and as heat
spreads through the food by conduction, just as in a traditional oven, the food cooks from the outside
inwards.
In a microwave oven, electricity is converted into microwaves
by the MAGNETRON.
Reflection
The microwaves bounce off the metal walls and the metal door
screen.
Transmission
Then they pass through the cooking containers to be absorbed
by the water molecules in the food, all foods contain water to a
more or lesser extent.
Important notes
How microwaves cook food
The dish used to cook or reheat the food will get warm during cooking, as the heat conducts from the
food. Even in micro waving, oven gloves are required!
MICROWAVES CANNOT PASS THROUGH METAL AND THERE FORE METAL COOKING
UTEN SILS CAN NEVER BE USED IN A MICROWAVE, FOR COOKING ON MICROWAVE ONLY
Foods Not Suitable for Cooking by Microwave Only
Yorkshire Puddings, Souffles, Double Crust Pastry Pies.
Because these foods rely on dry external heat to cook correctly, do not attempt to cook by micro wave.
Foods that require deep fat frying cannot be cooked either.
Standing time
When a microwave oven is switched off, the food will continue to cook by conduction – NOT BY
MICROWAVE ENERGY. Hence STANDING TIME is very important in microwaving, particularly for
dense foods i.e. meat, cakes and reheated meals (Refer to page 12).
Boiled Eggs
Do not boil eggs in your microwave. Raw eggs boiled
in their shells can explode and cause serious injury
13 Amp fused socket
