Coffee roasting | what are the common problems encountered during coffee roasting?

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The problems commonly encountered in coffee roasting are as follows:

First, when the preheating temperature of the oven is not enough, the coffee beans are immediately put into the oven, which prolongs the baking time. Therefore, the baking loss is large, and the color of coffee beans is light, which is due to the lack of heat and the lack of full coking of the skin, resulting in a lack of color and rough internal tissue.

Second, the oven temperature is too high, when roasting coffee, the surface forms a hard skin prematurely, which makes the internal tissue expand, and because of its fast surface coloring, the operator mistakenly thinks that the product has been baked and ends the baking ahead of time. The inside of this kind of bean is sticky and dense, it doesn't expand as it should, and it doesn't have a normal flavor.

Third, the gap is too long after preheating. Too much heat accumulates in the internal furnace which has been dry and hot for too long. As soon as the coffee beans enter the oven, all the heat sources will concentrate on the surface of the beans at the early stage of the baking process, forming too strong heat, and then the heat disappears and cools rapidly. The unstable temperature in the furnace makes the coffee beans difficult to ripen inside.

Fourth, the baking time is too much or not enough. The baking temperature and time should be adjusted according to the number of beans. A small number of baking silos have more space, and the metal conducts more heat radiation, so the temperature is lower, while when the quantity is larger, the temperature can be higher. The baking time also needs to be adjusted flexibly. The heating of beans in the oven is nothing more than the absorption of heat from the appearance and surrounding to the center of the beans, so the baking can be observed from the changes in the appearance of the beans.