Coffee is brown or black before drinking, but this is because the green beans are roasted and then burnt.
This process of roasting the beans is called roasting, and the roasting process affects the coffee's taste.
Some coffee shops and cafes roast their own beans, while others purchase them from roasters.
Mass-production roasters are capable of roasting over 100 kg in a single roast.
Most roasters use drum-type roasters, either city gas or propane.
Drum-type roasters come in three types: (1) direct-under type, (2) hot air type, and (3) semi-hot air type.
Direct-under types are:
(1) Direct-under type
A flame hits the beans from below the drum, transferring heat directly to the beans. It is characterized by its powerful direct-under type, which requires care to avoid unevenness and burning, but produces a fragrant roast.
(2) Hot air type
The beans are roasted using a large amount of hot air passing through the drum. This tends to produce a uniform roast. This is suitable for roasting to bring out the acidity.
(3) A type that combines (1) and (2) and uses both drum heat and hot air. Many of the world's latest models use this method.
When installing this type, smoke and odor control measures are necessary, and regulations are often strict in urban areas, so the installation environment must also be considered.
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