The milk foam in the coffee is the key milk foam.

Author: yi zhang

Link: http://www.zhihu.com/question/20360485/answer/34507011

Source: Zhihu

The copyright belongs to the author. Commercial reprint please contact the author for authorization, non-commercial reprint please indicate the source.

The foam of milk

Just this question, I can write another article, how to get the right milk foam is also a knowledge!

There is an article called "the formation of Milk Bubble", which is very detailed and good. Yun inadvertently wrote an article called "Laboratory Cappuccino Bubble", which is interesting about how to consider increasing the foam of coffee in the vending machine.

To put it simply, it is necessary to have the structure of protein in milk, the stable structure of fat, and the right temperature to make the protein active. It looks similar to the structure of coffee fat foam, and the particle size is just at the micron level.

So what should you pay attention to when making foam with a coffee maker?

Screenshot from video: Quick Tip: Milk for Lattes and Cappuccinos

Do you see the difference?

There is hot steam in the pipe, and if you put the tube under the liquid surface, you will get heated milk foam with twice the volume, and the whole system is a very uniform microbubble system, which is used for latte milk bubbles, while cappuccino puts the tube close to the liquid surface. in fact, this pipe has three small openings, two under the liquid surface and one on the liquid surface, manually adjusted to press more gas into the surface. In this way, the milk foam can be turned into three times the volume, and at this time you will hear a very shrill sound, the clamor of the air between the cracks in the liquid!

So when you go to a cafe to order a cappuccino, you will hear a harsh sound, while when you order a latte, there is basically no such sound except at the beginning and end of the jet. Does it feel like it's a little bit higher?

Now! Suppose we have two symmetrical bubbles, how can we mix them together to pull flowers?

This is the artist's business. Basically, I have nothing to do.

But! Have you ever wondered why it is called Lahua?

Why use this "pull"?

When on earth can you draw flowers when you pour down the bubbles?

I think: when you pour down the bubble, it should be fast and then full. When the speed is fast, the bubble will sink because of the impulse, and then bounce back to the bottom, or float because of the force of the liquid. When you see that the color of the liquid on the right half of the picture has become much whiter, you can start to "pull". Pull the bubble cup a little further to observe the liquid state, and then pull closer and continue to pour. Shake the cup more evenly.

​, this is the first important pull!

When the white and brown patterns have appeared on the surface, you should start drawing flowers slowly.

In the picture, you get this pattern while shaking left and right, and pull a straight line back at the end to get the leaf shape as shown in the picture.

In the picture, you get this pattern while shaking left and right, and pull a straight line back at the end to get the leaf shape as shown in the picture.

If you don't shake, you will get a circle layer by layer, and then pull back to have a heart shape, which is a favorite of girls.

Some people ask, why after watching so many flower-pulling competitions, it is always either heart-shaped or leaf-shaped, is there any advanced fresh point? Yes, but there can be no triangular five-pointed stars, because they are a flowing system, mainly because the flow speed of the two kinds of bubbles is slower than that of liquids, and it takes some time to disperse after mixing together, so while they have not yet mingled with each other, we can seize the time to draw a picture. In addition to two-dimensional drag, it can also be piled into space, but it also moves at a speed visible to the naked eye.

​ but the world always tends to increase entropy, so this kind of art will disappear soon, but you can add stabilizers and additives to keep the foam stable. I have tried a stabilizer that can be applied to any liquid and can make a vegetable green foam that does not deform for more than ten minutes. It's fun. In the picture above, the foam of the bear is so tight and well-defined that it can be painted. I don't know if any stabilizer has been added.

​ ​ said that this bear can forget it for a while, although it is very doubtful whether it is drinkable, but the Hanamichi Sakuragi pictured above cannot be called Lahua at all. It's really heartbreaking. I don't know what makes a particularly solid bubble, and then draw on it directly with coffee. Can it be called pull flower? It can only be called painting!