Common types of roasters

(a) common types of roasters

1. The hot air type

The hot air type bean dryer uses a blower to draw in air and then let the air pass through a heating coil to raise its temperature. The hot air is used as a heating source to roast the coffee beans. The hot air can not only provide the temperature needed for roasting, but also use the power of the air to stir the beans, killing two birds with one stone.

Advantages: High thermal efficiency, fast heating, raw bean heating is more uniform, easy to control.

Disadvantages: Because of the high heating efficiency, it is easy to lead to too fast heating, resulting in beans "sandwich", and the temperature is too high to make the caramelization reaction is not sufficient.

Flavor characteristics: The acidity is obvious, the flavor is clean and simple, but the flavor is not rich and lack of depth, and the deep baking is easy to produce pungent taste.

2, direct fire

As the name suggests, a direct fire uses a flame to heat coffee beans directly. Evolution up to now, direct fire "fire" in addition to the general flame (including gas fire and charcoal fire), but also including infrared and electric heat pipe.

Pros: Longer baking time, full caramelization, rich flavor,

Disadvantages: easy to cause uneven roasting, if the temperature is not well controlled, it is easy to burn the coffee beans, forming a scorched bitterness.

3. Semi-straight fire and semi-hot air

The baking method combining the advantages of direct fire and hot air is the mainstream of commercial baking machines at present. Semi-straight roasting is similar to straight roasting, but because there are no holes in the outer walls of the roasting container, the flame does not directly touch the beans; Besides plus the convulsions of the equipment, hot air outside baking container import baking efficiency of ascension in the baking chamber into the ventilation equipment another function is will fall off the silver leather (outer membrane attached to the coffee seeds) absorption, avoid silver leather in the baking room because of the high temperature burning, which influence the flavor of the coffee beans.

Semi-direct fire semi-hot air machine has the advantages and disadvantages of both direct fire and hot air, but the heating mode is changed according to the regulation of hot air and boiler speed. The more hot air is opened, the faster the speed is close to hot air; On the contrary, the closer to direct fire.