1. Drum roasting (professional level technology)
Drum roasting is a classic and one of the most popular methods of thermal processing of beans. It is carried out in special machines called drum roasters, where the beans are placed in a rotating drum and treated with hot air. The technology allows for even roasting of the beans due to constant movement and controlled temperature.
How does a drum roaster work?
- Preheating: Before the process begins, the drum is heated to the desired temperature.
- Loading beans: Green coffee is placed in the drum, where its gradual heating begins.
- Rotation: The beans are continually stirred to avoid burning and ensure even roasting.
- Temperature control: Temperature and time are adjusted to achieve the desired flavor profile.
- Cooling: After reaching the desired roast level, the beans are quickly cooled to stop the thermal treatment.
Taste features:
Drum roasting allows for maximum precision in revealing the beans. For example, light roast preserves fruity and acidic notes, while dark adds rich chocolate and caramel undertones.
2. Hot air roasting (Fluid Bed)
Hot air roasting is a method where green coffee beans are processed by a powerful stream of heated air. This method is used both on an industrial scale and at home using compact machines. The key feature of the technology is that the beans do not come into contact with the heated surface, ensuring the cleanliness of the process and minimizing the risk of burning.
How does hot air roasting work?
- Preparation: The beans are loaded into a special chamber where hot air is blown underneath them.
- Constant movement: The light beans "fly" in the air stream, not burning and being processed evenly.
- Temperature control: The air temperature and flow rate are adjusted.
- Cooling: After reaching the desired roast level, the beans are quickly cooled to stop the process.
Taste features:
This method is ideal for light and medium roasting, preserving acidic and fruity notes. At the same time, dark roast using this method requires careful control to avoid charred notes.
Tip for home enthusiasts:
If you want to try hot air roasting, start with small batches of beans and machines like air poppers for corn. Adjust the time and temperature to find your perfect flavor!
3. Contact roasting (in a frying pan or in a roaster without a drum)
Contact roasting is a method where coffee is roasted on a heated surface, such as a metal frying pan or a roaster without a drum. This approach requires manual intervention, as the beans need to be stirred regularly for even heating. Although this method is often chosen by coffee lovers, it is also used by small coffee shops to experiment with roasting.
Pros:
- Ease: Minimal equipment requirements—just a frying pan or a simple roasting surface.
- Experimenting with profiles: The ability to finely tune the process to create unique flavors.
- Accessibility: This method is suitable even for beginner roasters.
Cons:
- Labor-intensive: The need for regular stirring requires time and concentration.
- Risk of over-roasting: Due to direct contact with the heated surface, there is a chance of uneven roasting or burning of the beans.
- Limited volume: Suitable for small batches of beans, which can be a drawback for large-scale production.
Contact roasting is an accessible way to try your hand at roasting and understand the subtleties of flavor development in the beans.
Tips for choosing a method
- For light roasting, it is better to use drum or hot air roasters, as they emphasize fruity and acidic notes.
- For dark roasting, infrared or drum technologies work well, revealing rich chocolate and caramel tones.
Interesting fact
In recent years, many companies have begun to use artificial intelligence and automated systems for adjusting roasting profiles. This helps achieve flavor consistency, minimize errors, and take customer preferences into account.
These technologies allow for creating beans with the perfect flavor and aroma for every coffee lover.