HEAT TRANSFER

The whole process  and principle of baking, revolves around the transfer of heat from a heat source to the product being baked. How this is achieved has a direct influence and result on the final baked product.


There are 3 main forms of heat transfer.

                                    CONVECTION 

When a liquid or gas is heated, they expand. As it expands and rises it is replaced by cooler gas/liquid which is then heated, this will then rise and the, by now, cooler gas/liquid will drop back down to be reheated causing a cyclic movement

                                     CONDUCTION

Heat travels through a solid object or is in contact with a heat source, certain materials are better conductors of heat. e.g. metals.              Materials that do not conduct heat such as wood are known as bad conductors.

                                        RADIATION

The transfer of heat without matter. The sun is a very good example of radiated heat as is an electric fire or the obvious radiator from a central heating system. Microwave cooking is also based on radiated heat.

 

heat conduction




 

convection

 

conduction


 

radiation

OVENS 

The oven is the one piece of equipment that you must have in order to be able to carry out any baking. It is quite possible to produce a loaf of bread with just your hands and an oven and so this is exactly the way that the first loaves of bread were made many thousands of years ago.

The first original oven was simply a hole in the ground in which a large flat stone was placed in the bottom. A fire was then made on top of the stone and burnt until the stone was thoroughly heated. The fire  would then be removed and the dough placed on the hot stone. To keep the heat in until the dough was baked, a large stone and earth would have been placed on top to help retain the heat. The oven was born.