The transference of heat to food
All methods of cooking depend on one or more of the following principles.
Heat passes from its source in direct rays until it fall on an object in its path such as in grilling.
CONDUCTION
This is the transferring of heat through a solid object by contact. Some materials for example, metal used for pans, transfer heat more quickly than, say, wood used for wooden spoons. Conduction is the principle involved in the solid electric ranges.
CONVECTION
This is the movement of heated particles of gases or liquids. On heating, the particles expand, become less dense and rise. The colder particles sink to take their place, thus causing convection currents, which distribute heat. This principle is used in heating a gas oven and in heating of liquids.
BOILING
Definition
Boiling is the cooking of prepared foods in a liquid at boiling point. This could be water, court bouillon, milk or stock.
Purpose
The purpose of boiling is to cook food so that it is:
Ø Pleasant to eat with an agreeable flavour,
Ø Of a suitable texture, tender or slightly firm according to the food,
Ø Easy to digest and safe to eat.
Methods
There are two way of boiling:
Ø Place the food into boiling liquid, re-boil, then reduce the heat for gentle boiling to take place, this is know as simmering.
Ø Cover food with cold liquid, bring to the boil, and then reduce heat to allow food to simmer.
Effects of boiling
Gentle boiling helps to break down the tough fibrous structure of certain foods, which would be less tender if cooked by other methods.
Advantages of boiling
Ø Older, tougher, cheaper joints of meat and poultry can be made palatable and digestible.
Ø It is appropriate for large-scale cookery and is economic on fuel.
Ø Nutritious, well-flavoured stock can be produced.
Ø Labour saving, as boiling needs little attention.
Ø Helps to tenderise the fibrous structure, extract starch and flovour from certain foods.
Ø Can avoid damage to foods, which would lose their shape if added to boiling liquid.
Ø Is suitable for green vegetables as maximum colour and nutritive value as retained, provided boiling is restricted to the minimum time.
Ø Seals in the natural juice as with meat.
Time and temperature control
Temperature must be controlled so that the liquid is bought to the boil, or re-boil, then adjusted in order that gentle boiling takes place until the food is cooked to the requires degree.
General rules
Ø Select pans, which are neither too small nor too large.
Ø When cooking in boiling liquid ensure there is sufficient liquid and that it is at boiling point before adding food.
Ø Frequently skim during the cooking.
Ø Simmer whenever possible so as to minimise evaporation, maintain volume of liquid and minimise shrinkage.
Safety
Ø Select containers of the right capacity - if they are too small there is danger of boiling liquid splashing over, forming steam and causing scalds.
Ø Always move pans of boiling piqued on the stove with care.
Ø Position panhandles so that they do not protrude from stove of become hot over the heat.
Ø Extra care is required when adding or removing foods from containers of boiling liquid.
