Too much froth means that the milk is not dense enough, and it is rough, and the roughness of the milk froth will have an effect on the taste of the coffee. This problem occurs when the milk is allowed to breathe during the milk froth fusion stage. Milk stick is not too close to the wall of the cylinder, slightly to the center part of a little bit, the first two or three seconds of shallow insertion of large bubbles, followed by a sharp lift of the cylinder, and do not change the angle, look at the liquid surface gradually appeared in the vortex, and no longer have to enter the air bared sound (at this time, the steam will be quickly cut the large bubbles into a dense milk froth).

The basic principle of milk foaming is to use steam to punch the milk, so that the liquid milk into the air, the use of milk protein surface tension, the formation of many small bubbles, so that the volume of liquid milk expansion, become foamy milk bubbles. In the process of foaming, lactose is dissolved in the milk because of the elevated temperature, and the use of foaming to make the lactose sealed in the milk, and the function of milk fat is to make these small bubbles form a stable state, so that when drinking these milk bubbles, small bubbles will break in the mouth, so that the flavor and aroma substances have a better distribution of amplification, so that the milk produces a sweet and thick taste and texture. And when fused with coffee, the adhesion between the molecules will be stronger, so that the coffee and milk fully combined, so that the characteristics of coffee and milk can be highlighted, but also fully integrated together to achieve complementary role.