The structure of the coffee roaster is content that many people are interested in and wonder about. Today, coffee roasters have become important in the coffee production process, greatly influencing the quality of the finished coffee before it reaches the consumer.
1. Basic requirements of coffee roasters
For the coffee roasting process to be complete and to produce a quality product, some basic requirements are set for all types of coffee roasters :
– The coffee roasting temperature of the machine must reach 185 degrees Celsius to 280 degrees Celsius.
– Coffee beans must be continuously moved in the roaster to ensure ripening without graying or burning.
– Fast airflow to exchange gas with the outside and treat exhaust smoke during roasting.
– The machine operates for a suitable time for the coffee beans to be fully ripe.
2. Types of coffee roasting machines
Coffee roasting machines are divided into two main lines, which are the Single-pass and Recirculation series. The airflow after the operation will not be reused for the Single-pass line but sent straight out into the air through the silk shell collection cyclone system. As for the Recirculation line, the hot air stream will be reused.
3. Types of coffee roasting machines and their structure
3.1. Classic Drum Coffee Roaster
This coffee roaster has a steel horizontal cage, cylindrical, flat, continuously rotates in a circular orbit, and has a furnace below the cell. The machine has a fan that sucks hot air through the coffee beans while roasting and then exhausts them through the chimney. The roasting cell of the device will evenly mix the coffee beans. After the coffee is roasted as desired, it will be discharged into a tub with an air suction motor to help cool it quickly.
Good classic Drum coffee roasters usually have a roasting cage structure consisting of 2 layers of steel with small gaps to limit technical errors such as facing, tipping, scratching, etc.
3.2. Drum coffee roaster indirect heat transfer
This type of coffee roaster will transfer the heating heat from the furnace to the coffee roasting cage. This type of machine has the advantage of avoiding direct fire with the roasting pan, so it allows roasting coffee at a higher temperature, shortening roasting time and limiting scorching of coffee beans. Like the classic Drum roaster, this roaster mixes the beans while roasting and cools the beans quickly in the more excellent outside.
3.3. Fluid-bed coffee roaster
This type of coffee roaster uses high-speed hot air to mix and stir the beans instead of the previous roasting cage in classic machines. Therefore, the device has a more compact design. On the other hand, the Fluid-bed coffee roaster does not have a separate cooling cage, but the roasted coffee beans will be cooled through the hot air blowing system when the machine’s furnace mode is turned off.
3.4. Coffee Roaster Recirculation
Unlike the Single-pass roasters mentioned above, the Recirculation coffee roaster will reuse the recovered heat stream to save more energy. This machine provides a higher and more stable roasting temperature, shortens the roasting time, and the automatic roasting process ensures stability safety and saves fuel costs.
4. Some vital technical parameters of coffee roasters
Although there are many types on the market today, the main parameters that help buyers choose a coffee roaster suitable for their wishes are:
– General information includes:
- Capacity: for example 8 to 12kg/hour.
- Roasting time per batch: 10 to 15 minutes.
- Gas consumption (for gas-powered machines): 4-5 kg of gas/100kg of coffee.
- Noise level: < 70Db.
- Total power capacity: 0.8 – 0.85 kW.
- Rated voltage: 220V
- Roasting technology: direct heating.
- Material: electrostatic steel.
- Frame structure: high-strength steel.
– Drum design:
- Material: heat-resistant steel.
- 3-phase reducer motor made in Korea, Japan, …
– Thermal fan: withstand temperatures above 300 degrees Celsius.
– Cooling table: made of 304 stainless steel, fast cooling, with dust collection system, shell.
– Control cabinet:
- Control device: FIG
- Dynamic equipment: thermal relay, CB, contactor, etc.
Hopefully, with the information provided in this article, readers will have a better understanding of the structure of each type of coffee roaster, the advantages of each class, and a few technical parameters to help you refer to buying a coffee roaster. The most suitable coffee roaster for its operations.