In the coffee industry, different coffee varieties such as Robusta and Arabica are thermally treated with hot air in roasting machines, such as the NEOTEC type RFB Junior, to separate the seeds from the coffee cherries. Roasting takes place at temperatures of approx. 220°C and, depending on the degree of browning, over a period of 30 seconds. To achieve uniform browning, the coffee beans are constantly circulated with the incoming air in a fluidized bed process.
During the roasting process, on the one hand, the silver skins adhering to the green coffee flake off, and on the other hand, on the basis of the Maillard reaction, the conversion of peptides with reducing sugars from the starch, lipids and proteins to aroma substances and melanoidins takes place.
Once the final product has been obtained, the coffee must be cooled rapidly in order to maintain the quality achieved and to avoid post-roasting. Cooling is achieved, among other things, by a quenching process with water.