Cooking Methods and Heat Transfer

The microwaves are reflected within the metal interior of the oven where they are absorbed by food. Microwaves cause water molecules in food to vibrate, producing heat that cooks the food. For example, when cooking a microwave cake in-a-mug.

Conduction is the process of heat being transferred between objects through direct contact. As the heat energy from the cooker hob or oven is transferred into the pan, it makes the metal atoms start to vibrate. As they vibrate, they knock against adjoining atoms and pass on the heat energy, then they pass it onto others, and so on. A good example is frying an egg in a pan. 

Where food is heated by a moving heat source such as hot air inside an oven that is circulated by a fan. As the amount of heat energy going into the water increases, the water molecules start to move upwards where the water is cooler, and collide with other molecules as they do so, thus passing on the heat energy into the food cooking in the water, such as rice or pasta.

Steaming, boiling, simmering, blanching, poaching and braising are all water based cooking methods.

Disavatages: Boiling: Needs attention, slow, flavour vitamins and minerals lost in cooking liquid. Steaming: Slow, little flavour added, lacks texture. Poaching: Food shrinks, little flavour added and slow. Braising: Prolonged cooking can minimize the nutritional value of food because vitamins and other nutrients are degraded by heat.

Advantages: Boiling: It is suitable for large scale cooking. Boiled food is also digested easily. Steaming: It preserves the main nutrients. As there is no direct contact with water, the nutritional substances in food are not lost. Poaching: The food you cook will turn out succulent and tender. Braising: Meat and vegetables will have a richer taste because all the juices and flavors combine and seep in during the slow cooking process. 

Baking, roasting, grilling and dry frying are all dry cooking methods.

Disadvantages: Baking: Food can be overcooked, slow. Roasting: Slow, takes time to prepare, danger of overcooking. Grilling: Needs attention, not suitable tough meat, danger of over cooking and burning the food. Dry frying: can increase a meal's fat content considerably if done incorrectly. 

Advantages: Baking: Baked foods are considered healthy because of their low-fat content. Roasting: Many vitamins stay in the food rather than being cooked away. Grilling: Food cooked on a grill is significantly lower in fat and calories. Dry frying: Keeps fat to a minimum and doesn't have as much fat as deep fry.

Shallow frying, stir fry and deep frying are all fat based cooking methods.

Disadvantages:  They all need constant attention, splatter grease, grease indigestible and high calories- contributes to heart disease, obesity and Type 2 diebetes.

Advantages: You can could food much faster with deep frying than you can with other methods. Food that is cooked in a deep fryer always tastes better than food cooked on a stove or in the oven.

To change or improve the taste of the food e.g vanilla being used to make cake. To change or enhance the appearance of the food e.g. using rice to make fried rice, preserving mango to make jam. To change the texture (the way something feels) of food e.g. toasting bread to make it crunchy.

·To kill bacteria and make food such as raw meat and eggs safe to eat.

·To develop flavours and improve the taste of food

·To soften fibres in meat and vegetable and make them easier to eat and digest

·To improve the keeping qualities of foods so that they can be used for longer periods.

·To give variety to the diet.