In this article, we invite you to discover some types of coffee roasting machines and their basic structure.
1. The basic requirements of coffee roasting machines
For the coffee roasting process to be completed and to produce qualified products, some of the basic requirements are arranged for all coffee roasting machines such as:
- The roasting temperature of the machine must reach 185 degrees C to 280 degrees Celsius.
- Coffee beans must be continuously moving roasted in the roasting machine to ensure the fullest of ripeness without burning.
- Fast flow of gas to exchange air with outside and exhaust fume treatment during the time of roasting.
- The machine works well to have enough time for coffee beans to ripen.
2. Some types of coffee roasting machines
Coffee roasting machines are divided into two main types, Single Pass and Recirculation. For the Single Pass, the airflow after the operation will not be reused, but will be directly carried out of the air through the kiln shell collecting system. While Recirculation will let the hot air be re-used.
3. Some types of coffee roasting machines and its structure
3.1. The coffee roasting machine with classic Drum
This coffee roasting machine has roasted cage made from steel, cylinder, horizontal, rotate continuously in a circular orbit and has a burner under the cage. The machine also has a hot air exhaust fan to pass through the coffee beans when roasting and then flush out through the chimney. The roasted cage will mix the coffee beans together. After the coffee beans are roasted as expected, they will be discharged into the tank with tissue - air suction motor to cool them quickly.
The qualified coffee roasting machine with classic Drum usually has the structure of roasted cage includes 2 layers of steel which have a small clearance to limit some technical errors such as facing, tipping, screeching,…
3.2. The coffee roasting machine with indirect heat transmission Drum
This coffee roasting machine will transfer heat from incinerator to the rusted cage. This kind of machine has advantages of avoiding direct fire with roasted cage so it allows to roast coffee beans at higher temperatures, shorten roasting time and limit the burning of coffee beans. Similar to the coffee roasting machine with classic Drum, this machine also mixes the coffee beans when roasted and cools the coffee beans quickly in the cooled cage outside.
3.3. The Fluid-bed coffee roasting machine
This is the coffee roasting machine which uses the high- speed air to merge and mix coffee beans instead of the former roasted cage in some of classic machines. Thus, this machine has a more convenient design. On the other hand, the Fluid-bed coffee roasting machine has no individual cooling cage, but the roasted coffee beans are cooled through the hot air system when the appliance's stove is turned off.
3.4. The Recirculation coffee roasting machine
Unlike the Single pass machine above, the Recirculation coffee roasting machine will reuse the recovered heat to save energy. This machine provides higher roasting temperature, more stability, shortens roasting time, the automatic roasting process ensures stability, safety and save fuel costs.
4. Some main technical parameter of the coffee roasting machine
Although there are many types of machine on the market today, the main parameters that help buyers choose a coffee roasting machine that is suitable for their needs are:
• Capacity: Eg: 8 to 12kg / hour.
• Roasting time: 10 to 15 minutes/batch
• The amount of gas consumed (for gas fueled machines): 4-5 kg of gas / 100k kilos of coffee.
• Noise: <70Db.
• Total power: 0.8 - 0.85 kW.
• Rated voltage: 220V
• Roasting technology: direct heating.
• Material: electrostatic steel.
• Frame structure: high- strength steel.
Drum roasting design:
• Material: heat resistant steel.
• Speed motor with 3 phases made in Korea, Japan, ..
- Heat fans: standing temperatures above 300 degrees C.
- Cooling tables: made of stainless steel 304, fast cooling with dust and shell collection systems.
- Control cabinet:
• Control equipment: ABB
• Dynamic equipment: thermal relay, CB, contactor, ...
We hope with the information provided in this article, you will better understand the structure of each type of coffee roasting machines, the advantages of each type and some technical parameter to help you choose and buy the best suitable coffee roasting machine for your daily activities