En-2
General Guidelines
PIERCING
The skin or
membrane on
some foods
will cause
steam to build
up during
cooking.
These foods
must be
pierced or a
strip of skin
should be peeled off before cooking to allow
the steam to escape. Eggs, potatoes, apples,
sausages etc, will all need to be pierced
before cooking. DO NOT ATTEMPT TO BOIL
EGGS IN THEIR SHELLS.
MOISTURE
CONTENT
Many fresh
foods e.g.
vegetables
and fruit, vary
in moisture
content
throughout the
season.
Jacket
potatoes are a
particular example of this. For this reason
cooking times may have to be adjusted
throughout the year. Dry ingredients e.g. rice,
pasta, can dry out further during storage and
cooking times may differ from ingredients
freshly purchased.
CLING FILM
Cling film
helps keep the
food moist
and the
trapped steam
assists in
speeding up
cooking times.
However it
should be
pierced before
cooking, to allow excess steam to escape.
Always take care when removing cling film
from a dish as the build-up of steam will be
very hot. Always purchase cling film that
states on the packet “suitable for microwave
cooking” and use as a covering only. Do not
line dishes with cling film.
VEGETABLES - Boiled potatoes benefit
from standing for 1-2 mins., however most
other types of vegetables can be served
immediately.
DEFROSTING - It is essential to allow
standing time to complete the process. This
can vary from 5 mins. e.g. raspberries, to
up to 1 hour for a joint of meat.
If food is not cooked after
STANDING
TIME, return to oven and cook for
additional time.
Dense foods e.g. meat, jacket potatoes and
cakes, require a STANDING TIME (inside or
outside of the oven) after cooking, to allow
heat to finish conducting to cook the centre
completely.
STANDING TIME
MEAT JOINTS -
Stand 8 - 10 mins. wrapped in tin foil.
JACKET POTATOES -
Stand 5 mins. wrapped in tin foil.
LIGHT CAKES - Stand 5 mins. before
removing from dish.
RICH DENSE CAKES - Stand 15-20 mins.
FISH - Stand 2-5 mins.
EGG DISHES - Stand 2-3 mins.
PRECOOKED CONVENIENCE
FOODS - Stand for 5 mins.
PLATE MEALS - Stand for 2-5 mins.
Microwaves are a form of high frequency electromagnetic waves
similar to those used in radios. Electricity is converted into microwave
energy by a magnetron tube. The microwaves travel from a
magnetron tube to the oven cavity where they are reflected,
transmitted or absorbed.
Reflection
Microwaves are reflected by metal similar to the way a ball would
bounce off a wall. Most metal cookware and utensils are not
recommended for microwave cooking, since they would produce
uneven cooking. Also, if a metal dish is placed close to the oven wall
(which is also metal), arcing (bluish sparks) could occur. Arcing can
damage an oven or cause a fire.
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 cooking containers. However, they will
get hot during cooking, because as food cooks, heat is conducted
from the food to the dish.
Absorption
Microwaves are absorbed by food. They penetrate to a depth of
about 2-4 cm. Microwave energy excites the molecules in the food
(especially water, fat and sugar molecules), and causes them to
vibrate very quickly. The vibration causes friction and heat is
produced. In large foods, the heat which is produced is conducted to
the centre to finish cooking the food.
Cooking with Microwave Energy
