As coffee is roasted, many physical and chemical changes take place in the beans

• Physical reactions
• Evaporation of water
• Internal pressure increase
• 1. cracking
• Volume increase (50% – 100%)
• Mass loss (12% – 24%)
• Dandruff formation
• Carbon dioxide output
• 2. Cracking
• Chemical reactions
• Pyrolytic reactions
• Maillard reaction
• Strecker distortion
• Caramelization
• Hydrolysis
• Oxidation

1.what is cracking?During roasting, the water that makes up the moisture in the coffee heats up, turns into steam and expands. In addition to the water vapor released, gases formed as a result of exothermic reactions create additional pressure. The expanded gases and vapor trapped in the core are released by cracking the cellulose structure. This is called 1st cracking. 1. The cracking always takes place at 160 °C. When the first cracking occurs, the roasting temperature should not be increased.What is the 2nd cracking?After the first cracking, gas production continues and pressure starts to build up again inside the core cells. Immediately afterwards, the structure of the core becomes more fragile. While the main cause of the first cracking is the accumulated water vapor, the main cause of the second explosion is the carbon dioxide that starts to increase as a result of roasting.