Italian coffee knowledge-milk foam in the flower when the role of pull

I. Methods used in teaching students:

The first step is to understand the correct operation process of the coffee machine steam system, understand the purpose of the empty steam pipe before and after the milk bubble, and understand the importance of towels and cleaning in coffee making.

The second step is to learn how to touch the milk surface with the nozzle, the position of the selected point, and the depth of the selected point.

The third step is to recognize two temperatures. One is the temperature at which the foam starts and ends, and the other is the temperature at which the foam is made. These two temperatures are very important for beginners, which is directly related to whether the principle of milk foam is mastered. To start with foaming, the milk is initially cold (preferably sufficiently refrigerated at 5 ° C), which can extend the foaming time so that it can foam fully and finely, and then open the steam valve to foam the milk. Foaming to the same temperature as our body (feel neither cold nor hot), foaming cut-off. Because our hand temperature is about 30° C, so I personally think that the temperature of milk foam can be mastered between 65-70 ° C. Because if it is too hot, it will destroy the nutritional value of milk.

Next, let's talk about the temperature at which the frothing stops. In fact, there are many theoretical statements about this temperature, which are unknown here, and we will talk about feelings when discussing the flavor of liquid milk in the future. Let me just say what this temperature feels like on the hand. This temperature is hot when we feel it with our hands (in continuous heating), but it can last for two or three seconds; when the temperature is reached, stop heating (stop heating the rear end feels very hot in the hand, but it can be held).

In some places, thermometer is used to measure. I think this teaching method is not good. Technology is something that needs people's heart to understand. It is not very beneficial to improve people's own technology with the help of external forces.

The fourth step is to recognize a dead angle between a milk frothing cylinder and a coffee machine steam pipe. Read a lot of domestic and foreign barista operation to play milk foam, plus their own constant attempts, found that there is a dead angle to play milk foam, just like playing video games, some dead angles are bullets can not hit you, but you can hit others. This angle is very troublesome to say in words, probably the cylinder mouth of the flower cylinder must be lifted, and the cylinder body should be inclined according to the rotation direction of the milk foam.

Step 5 Find the vortex. The role of this vortex is to foam out of the coarse foam through the vortex pulled to the surface below, so that the surface clean. Vortices have many states, and each one needs to be observed and remembered. This is a very deep point, I simply point it, to have a vortex, steam pipe nozzle can not be too deep under the milk.

The sixth step is to pull the flower jar down and up. The nozzle is in good contact with the milk surface, that is, open the steam valve. At this time, the flower pulling cylinder moves downward very slowly, and you will hear the "eat" steam and milk "shear"(about shear force, when discussing the principle of milk foaming later, talk slowly!) The sound emitted is commonly known as "intake sound". Air intake to human body temperature this sound can no longer appear, otherwise, the surface will have a particularly large coarse foam.

At this time, move the pull cylinder up a little (only a little, this is very important, many people understand that it is continuously moving up, this is very wrong), so that the steam nozzle leaves the shear surface, so that no "eat" sound can be heard. At this time, by adjusting the angle of the pull cylinder, remember that it is the angle, not the position of the nozzle and the surface (very small angle adjustment), find the vortex, pull the coarse foam of the foaming stage off the surface, and continue until the temperature reaches the hot temperature.

Step 7 Know how milk is steamed and how to handle foam. After the milk is whipped, it is not our ideal milk foam, but in a layered state, the lower layer is heated milk, and the upper layer is whipped "milk foam", so we have to treat the whipped milk.

Shake up and down to remove coarse foam from the surface. Shake to mix the hot milk with the top foam to form foam. This step is a good key, some friends do not pay special attention to this point, then all previous efforts have been wasted.

Before the eighth step, the milk foam has been in a shaking state in the flower jar to avoid the layering caused by this surface to appear again. This is a professional habit and requires that it must be cultivated.