Roasting machines are roughly classified into three types: direct flame type, semi-hot air type, and hot air type. The flavors and flavors produced by each format vary, but they also vary greatly depending on the skill of the roaster.
・ Direct fire roasting machine
A roasting machine that directly heats raw beans to roast them. The body of the rotating drum that holds the beans is made of punching metal and has many holes. Raw beans are roasted by the hot air that enters from there and the conduction heat from the drum.
The feature of the direct-fired roasting machine is that the beans can be roasted by directly applying flame or hot air to the beans through punching metal. The temperature of the heat source is close to 1500 ° C, and the heat supply to the beans tends to be extreme, which can create a unique aroma and taste.
・ Semi-hot air roasting machine
The distance of the heat source is almost the same as that of the direct type, but it is a roasting machine whose body of the rotating drum is made of iron plate. It is easy to finish with a sour and clean taste, and is often used for high-quality coffee.
Since the conduction heat from the drum is transferred to the beans more than other roasting machines, the characteristic is that the range of roasting can be expanded by adjusting the conduction heat. The appeal of the semi-hot air type is that it is easy to get close to your favorite taste.
・ Hot air roasting machine
A roasting machine that roasts by sending hot air into the drum from a heat source separated from the rotating drum. Compared to the direct flame type and semi-hot air type, the effect of conduction heat is small, and the finish is adjusted according to the temperature and air volume of the hot air.
It is easy to handle and has a stable finish, so it has high production efficiency and is used by many large-scale roasters. In addition, since the time to apply hot air can be adjusted widely, the degree of freedom of roasting is high, so it is often used for roasting specialty coffee.