Cooking techniques vary depending on the way heat is transmitted to the food. They can be divided into six groups: cooking in water, with steam, by contact with a hot surface, deep frying, by braising, and baking in an oven. These traditional techniques are now joined by the techniques of cooking in a microwave or vacuum cooking.
Cooking food in water heated to 80°C enables proteins to coagulate. At boiling point, that is 100°C, it makes starch digestible.
Steam cooking can be carried out under normal pressure in steamer baskets, or under augmented pressure in pressure cookers. The latter are an application of a technique invented by the French inventor Denis Papin as far back as the 17th century.
The delicious aromas that are released during the preparation of potato rissoles or grilled meat on a very hot surface are due to countless aromatic compounds created by a reaction between carbohydrates and proteins. This is called a Maillard reaction, named after the French biochemist who explained the phenomenon in 1912.
Immersing food in hot oil (160°C to 180°C) enables fast cooking while giving the food a crispy texture. Deep frying also creates many aromas.
Slow cooking or braising is carried out in closed containers with very little liquid. It tenderises plant fibres and dissolves the protein sheath that surrounds muscle fibres and makes meat stiff.
In a traditional oven, heat can be transmitted either by direct contact on the oven floor, by hot air, by pulsed steam or by radiation from a coil.
The first microwave oven appeared in 1953. It heats food by making the water molecules contained in the food vibrate. This vibration is caused by electromagnetic waves.
Vacuum cooking actually involves using water or steam to cook food that has been vacuum-packed in a sealed bag.