The coffee beans roasting process is a transformative journey. The coffee roasting process transforms raw green beans into aromatic, flavourful coffee, automatically bringing out the rich flavours and aromas locked inside green coffee beans. Understanding this process helps you appreciate the craft behind every cup of coffee.
Here’s how it works . . .
Step 1: Heating: The roasting process begins with heating the roaster. This heat source is crucial for starting the roasting process. For gas-fired roasters, a mixture of air and LPG gas is ignited and pumped into the roasting chamber. Electric roasters, on the other hand, use heating coils to achieve the desired temperature. Preheating ensures that the beans are exposed to consistent heat as soon as they enter the roaster.
Step 2: Roasting: The green coffee beans are loaded into the roaster, either in a rotating drum or a fluid bed chamber. The heat is applied evenly while the beans are tumbled or lifted to ensure uniform exposure.
As the roaster heats, the beans undergo a series of chemical changes:
- Drying Phase: The beans lose moisture and begin to turn yellow.
- Browning Phase: Sugars inside the beans caramelize, and aromatic compounds develop.
- First Crack: This audible crack signals that the beans have reached a light roast stage.
Temperature control is critical during this phase. Most roasting happens at temperatures around 200°C – 225°C, depending on the desired roast level. Roasting too quickly or unevenly can result in burnt or underdeveloped beans.
Step 3: Cooling: Once the beans have reached the desired roast level, they are quickly transferred to a cooling tray. Cool air is circulated to stop the roasting process and stabilize the beans’ flavours. Without rapid cooling, the beans may continue to roast, leading to overdevelopment.
Step 4: Reloading: After cooling, the roasted beans are removed, and the roaster is cleaned and prepared for the next batch, continuing the cycle. Consistent cleaning ensures the equipment remains efficient and prevents cross-contamination of flavours.
Pro Tip
Use a roaster with a viewing window to monitor the beans’ colour and development during roasting. Paired with a timer and temperature gauge, this helps achieve consistent results.
Conclusion
Regularly clean and maintain your roaster to ensure consistent quality and prevent overheating issues.