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The quantity or volume of a food can affect the amount
of cooking time. As the volume of the food is increased,
the time required to cook or heat the item increases
almost proportionately. If twice the amount of food is
placed in the oven, it will take almost twice as long to
cook. To determine the time for larger quantities, multiply
the individual serving time by the increased amount,
then reduce the total heating time by about 20%.
The density of foods can greatly affect the amount of
cooking time. Porous foods, such as breads, cakes or
pastries, will heat much more quickly than dense meats
of the same size. Porous foods absorb microwaves
quickly throughout. Meats absorb microwaves mostly at
the exterior surface, and the interior is heated by
conduction, increasing the cooking time. Meats can be
cooked in a sauce, if desired. Due to the moisture
content, a sauce will heat rapidly. The heat will transfer
to the meat, so the meat will heat faster due to heat by
conduction as well as by microwaves.
The starting temperature of foods affects the amount
of cooking time. Each temperature degree that the food
item is to raise must be supplied with a definite amount
of energy. Lower initial starting temperatures require
more energy and more time to cook. Therefore,
refrigerator temperature foods require a longer cooking
time than room temperature foods. Foods already
slightly warm will heat very quickly in the oven.
The moisture content of foods affects the amount of
cooking time. The higher the moisture content is in a
food the longer the amount of cooking time.
The fat and sugar content of foods affects the amount
of cooking time. Foods containing high fat and sugar
levels heat very quickly and may reach much higher
temperatures than foods having low fat and sugar levels.
Foods having lower fat and sugar levels require longer
cooking times.
The arrangement of food within a microwave oven
cavity affects the way in which the food cooks. A “round”
arrangement is best. Use round utensils whenever
possible. Also, arrange foods such as baked potatoes in
a circle, rather than in rows, for cooking. When only one
food item is being cooked, place it in the center of the
oven glass shelf for cooking.
Manipulation of Foods
Sometimes recipes suggest manipulating or moving food
during cooking. There are several forms of manipulation:
Stirring is required less often in microwave cooking than
in conventional cooking. In conventional cooking, you use
a spoon to move food up from the bottom of a pan to
evenly distribute the heat. In microwave cooking, you still
stir to redistribute the heat within some foods, but you
need to stir from the outside of a dish toward the inside or
center. If a recipe states to stir once or twice during
cooking, stir at approximately even intervals. For
example, in a 12-minute cooking period, if a recipe states
to stir twice, stir after 4 minutes of cooking and again,
after 8 minutes of cooking. However, it is not necessary to
be precise. Stir only when necessary. When using lower
power levels or settings, less stirring is required. Some
examples of foods which may require stirring are
puddings, some casseroles, some sauces, some soups,
and some egg dishes. Some foods can’t be stirred. These
foods are rearranged or turned.
Some foods can’t be stirred and should be repositioned
or rearranged during cooking. Some examples include
baked potatoes, cupcakes (in custard cups), and chicken
pieces. Rearranging allows for more even cooking of
foods. Foods which are cooked, covered or which are
cooked using lower power levels, usually require little
rearranging.
Turning foods over: Turning foods over is done to
distribute heat. Meat and poultry are two types of foods
which are sometimes “turned over.” Examples include
roasts, turkeys and whole chickens. Small meat items
such as poultry pieces may need to be turned over when
in casseroles, or when in a browning skillet.
