Coffee roasting process basic
Basically, roasting means transforming coffee beans from raw or green to brown. There are three main stages in roasting processing: Firstly, drying stage. Secondly, browning stage and finally, development stage.
Firstly, drying stage
Normally, the green or raw coffee has a humidity of 8% to 15%. We need to dry it before the actual roasting starts.
Secondly, browning stage
At about 160 ⁰C, the coffee starts to smell like toasted bread. This is when the Aroma precursors are starting to convert to Aroma compounds.
Finally, development stage
Beginning of development stage, the reaction becomes exothermic and the coffee cracks. The bean has collected energy that makes the coffee to explode during 2 stages before. Development time is when the wanted aroma compounds are developing. The length of this stage takes 10–30% of the total roasting time and depending on the desired flavor profile and roast degree.