To roast is to roast raw coffee. Roasting is a complex chemical phenomenon combining several transfers (heat, water and mass) and pressure differences. By heating, the water in the coffee beans, which consist of 10-12% moisture, evaporates. The roaster adjusts the temperature and cooking time to the nearest second. Once the master roaster has found the ideal combination, he records his recipe in specialized software that allows him to monitor, in real time, that the roasting is going according to all these parameters. Variations, however subtle, have an influence on the final result.