1、Steaming stage:

00 -10min; Xiadou-140c; This is an important process of the endothermic reaction of coffee beans. At this stage, the beans will slowly expand, and the color will change from green to white. The water will slowly evaporate from the heart of the beans because of the endothermic effect of the beans. The mother's mouth finds that the coffee is good to drink depends on this stage. When the water evaporates too fast, it is easy to cause the heart of the beans to be immature, the beans are easy to be bitter, and when the water evaporates too slowly, it will cause the taste of the coffee to be dull, The aroma is not rich.

2、Dehydration stage (before first explosion):

10 -15min; 140-180C; After steaming, the coffee beans will quickly change from white to light yellow brown. At this time, the coffee beans will continue to absorb heat and reach a burst. The coffee beans will change from expansion during steaming to shrinkage and dehydration. At this time, the moisture of the coffee beans will decrease rapidly. When the heat reaches the extreme point of the coffee itself, there will be an explosion reaction, which is the so-called burst.

3、First explosion stage (after the first explosion and before the second explosion):

15 -18min; 180-210C; After the explosion, you can smell it clearly. The aroma of coffee will change from grass to coffee coke. With the explosion, the coffee beans will burst and expand. Basically, coffee can be drunk from the beginning to the scorch, without the smell of grass, but the coffee at the beginning of explosion will be very sour and not bitter. As time goes on, the taste of coffee will be transformed into non sour and extremely bitter. Generally speaking, the next bean point will be determined by the flavor of coffee itself. When the sour taste is gone and the bitter taste is about to appear, it will usually be the next bean point of mother's mouth. At this time, the sweetness of the next bean will reach the point and the flavor will be improved. This point depends on the "flavor" of coffee itself. Due to the different growth environment, climate, soil and water, the "flavor" of coffee will be slightly different.

4、Secondary explosion stage:

18 -20min; 210 - beans; After the second burst, the coffee beans will slowly mature and emit charming aroma. When the endothermic reaches the second point again, the coffee beans will explode for the second time, which is the so-called second explosion. In the inner part of the epidermis, a space will be expanded, and the carbon dioxide in the coffee beans will continue to be discharged, resulting in the continuous rise of the internal temperature, the beginning of coking, turning into oil and seeping out of the coffee surface. At this time, the coffee flavor will be bitter, The aroma is strong. Starbucks usually bakes until this stage. If it continues, the coffee beans will slowly turn into coke, and there is no aroma except bitterness.