Explanation on the baking process and change of small coffee roaster the essential information of small roasting coffee shop

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Professional coffee roasting | is coffee roasting too complicated? A picture teaches you about the baking process.

Coffee roasting refers to the process in which raw coffee beans are transformed into ripe beans by heating in a roaster.

How well should the coffee be roasted? What's going to change? What beans are suitable for shallow baking and which beans are suitable for deep baking? This is a question often asked by many people I meet.

In fact, coffee beans go through a series of physical and chemical changes in the roasting process, which is extremely tedious and complicated. Different roasting processes and conditions will lead to different results of the same kind of coffee beans.

Changes in the roasting process of coffee

Generally speaking, fresh coffee beans are turquoise, and the color will gradually become lighter as the water content decreases over time.

(I) dehydration

When the roaster is preheated to a certain temperature, we slowly heat the raw coffee beans in the roaster, and the water between the cells in the beans becomes lighter and lighter because of the heat, and the color of yellow dried straw becomes lighter and lighter. The smell of beans has also changed from grass to toast, and the dehydration stage is over.

(2) to accelerate the fire

At this time, although the water between the cells has roughly evaporated, the water in the cell wall still exists. As the roaster continues to heat the water in the coffee bean cells and gradually absorbs heat and expands, the bean temperature rises slowly at this time. In order to make the following series of chemical reactions proceed smoothly, it is a very important key to heat up the bean temperature at this time.

(3) one explosion to reduce fire

When the bean continues to absorb the water in the coffee bean cell because the endothermic evaporation causes a series of chemical changes in the cell and produces a large amount of carbon dioxide, until the cell wall can not withstand the internal pressure to burst, the bean also changes from endothermic to exothermic so that the temperature rises rapidly. At this time, it is necessary to be able to immediately reduce the fire in order to strain the soaring bean temperature, otherwise the rapidly rising temperature will make the beans follow a series of chemical changes too fast and the transformation is not complete, which will cause bitter degradation and aromatic substances polymerization and other actions do not have enough time to react, that pot of beans will be destroyed, so the regulation and control at this stage is very important.

(4) second explosion regulation

Coffee beans after an explosion to release a large amount of heat and adjust the fire will have a quiet period of 2 minutes and then slowly begin to absorb heat, at this time do not heat up with the fire, but can not lose temperature or stagnation, so the need for moderate adjustment of the heat source so that the temperature rise steadily to prepare for the arrival of the second explosion. When the cells in the coffee beans once again cannot withstand internal pressure and burst and produce a second burst, the sound of the second explosion is not as strong as that of the first explosion is presented in a small and rapid way. The firepower after the second explosion should also be carefully adjusted because the caramelized coffee beans are more fragile and can no longer stand too much firepower.

(5) Lower beans

When the coffee beans reach the roasting level we set, the beans are released from the oven, and the internal temperature of the coffee beans is still very high and constantly changing. Therefore, the beans must be cooled quickly after dropping the beans, otherwise continuous changes in the beans may make the baking deeper.

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