Coffee roasting | introduction of heat conduction, convection and radiation during roasting

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There are three ways: heat conduction, convection and radiation.

Conduction refers to when the heat is transmitted by the heat source, causing the surrounding molecules to vibrate and release heat, gradually moving from the high temperature to the low temperature. The conduction of stainless steel has the phenomenon of uneven heating, which can easily lead to colder and hotter parts of the pot.

Convection means that when the material is heated, the fluid material or gas rises due to the volume expansion and the decrease of density due to the heating action, and its position is supplemented by the colder and denser fluid exchange around it, and then rises by heating, and the surrounding material is added. Such a continuous cycle of heating motion is called convection.

Radiation does not need any medium, and the heat can be radiated directly to the object to heat it. * the radiation commonly used in food is the use of dielectrics, microwaves or infrared rays. In the specific operation of baking, it is often baked in two or three ways at the same time, depending on the environmental conditions at that time.