Must see for beginners-Ⅱ, the basic equipment for coffee flower drawing.

2bar, before brewing coffee, the pressure value shown by the pressure gauge is the water pressure of the inlet pipe itself, which is usually about 1-2bar. After pressing the brewing switch, it will show the set pressure, and you should pay special attention to one thing: when setting the brewing pressure, you need to fill the brewing handle with coffee powder, so the brewing pressure setting value is correct. Special attention should be paid to this because the pressure when using coffee powder is greater than when it is not.

Cooking pressure adjustment screw: the position of the cooking pressure screw is in the place of the water pump, and most of them need to remove some parts of the shell of the Italian coffee machine, but some Italian coffee machines are designed. The cooking pressure adjustment screw will be placed in an easy position. When adjusting the cooking pressure adjustment screw, it is necessary to loosen the screw line in the back section, and then rotate the front adjustment screw. And most of the adjustment directions are clockwise to reduce the pressure, counterclockwise to increase the pressure, and then tighten the fixing screw after adjusting to the set pressure value. however, there are still some Italian coffee machines where the cooking pressure adjustment screw rotates in the opposite direction.

two。 Commercial bean grinder

When the bean grinder adjusts the thickness of coffee powder, it only needs to rotate the turntable, and the direction of rotation adjustment scale is mostly clockwise, the thicker the coffee powder is, and the finer the coffee powder is when it rotates counterclockwise. On the other hand, the scale turntable of the commercial bean grinder is divided into two kinds: one is that there is a fixed clip on the scale turntable, and the adjustment of the scale is adjusted one by one, and the sales grid of the adjustment scale will vary according to the brand. Generally speaking, the smaller the adjustment, the better. Only in this way can we make minor adjustments. The other is that there is no fixed card bolt, so you can just turn the dial when adjusting, and you should also pay attention to grinding some coffee beans and withdrawing the coffee powder from the bean grinder trough after adjusting the dial turntable. Only in this way can the coffee beans grind out is the set thickness.

Five major brewing factors of espresso Espresso

The scientific definition of Italian concentration is as follows: coffee bean powder content-6.5g, boiling water temperature-90 ±5 ℃, cooking water pressure-9 ±2bar, cooking time-30 ±5 seconds. When we brew espresso, we must take the scientific definition as the basis, but because there are so many factors to pay attention to when brewing a cup of espresso, there are about 20 different influencing factors. We won't discuss it here.

Brewing pressure: the higher the brewing pressure, the higher the proportion of coffee chemicals extracted, but what percentage should be extracted is correct? There is no absolute standard brewing pressure value based on the condition and daily changes of the coffee beans used, but we can use the scientific definition of espresso as a basis to adjust to the correct brewing pressure setting.

The value of the boiler pressure, assuming that under the same atmospheric pressure value, because the volume of each boiler is different from the set level of the water level, the resulting effluent temperature of the cooking head will also be different, so the correct effluent temperature of the cooking head must be determined. When the boiler pressure is lower and the temperature is lower, the sour taste of the extracted coffee will be more obvious, and the overall flavor of the extracted coffee will be weaker; when the boiler pressure is higher and the temperature is higher, the extracted coffee coke will be more withered and the overall flavor will be heavier, so, we can use this principle as a basis for adjusting the flavor of extracted coffee.

The fineness of coffee powder: basically, the three controlling factors, namely, the amount of coffee powder, the power of filling coffee powder, and the thickness of coffee powder, are used together to fill out different coffee pressed powder densities so as to adjust and control the extraction degree of coffee. in terms of the fineness of coffee powder, the thicker most coffee powder particles are, the shallower the extraction degree is, and the more acidic chemicals will be. There are fewer bitter chemicals. On the contrary, the finer the particles of coffee powder, the deeper the extraction, the more bitter, and the less sour. However, some coffee beans will be different from the above principles because of the characteristics of their own beans, we should pay attention!

Amount of coffee powder: the more the amount of coffee powder, the higher the relative coffee concentration and mellowness, while assuming that under the same coffee pressed powder volume, when there is too much coffee powder, the density of coffee pressed powder will be too dense, resulting in insufficient extraction of coffee powder. When the amount of coffee powder is too small, the density of coffee pressed powder will be too loose, resulting in excessive extraction of coffee powder, so the appropriate amount of coffee powder can correctly extract the chemicals in coffee pressed powder.

The strength of filling coffee powder: the force of filling coffee powder will be determined according to the thickness of coffee powder and the amount of coffee powder, assuming that under the same coffee powder thickness and powder quantity, if the filling pressure channel is too large, the density of coffee pressed powder will be too dense, and the extraction time of water will be prolonged, resulting in excessive extraction. When the filling pressure channel is too small, the density of coffee pressed powder will be too loose. Resulting in insufficient extraction.

The state of the coffee extract: when brewing the coffee, you must observe the state of the coffee extract to check whether the correct coffee extract is extracted in accordance with your own set way. Because the state of the extract will vary according to the way the coffee beans are mixed, the degree of roasting, the adjustment of the Italian coffee machine, and the barista's brewing skills, it is not generally said that only the reddish-brown cream coffee extract is correct. Take the light and medium roasted coffee beans with northern Italian flavor, for example, the cream on the surface is not reddish brown, so when the tissue of cream is uniform, the alcohol is thick enough, and there is no excessive or insufficient extraction color, it is the ideal state of coffee extract.

The principle and method of milk foaming

a. Why use foamed milk?

The basic principle of milk foaming is to use steam to hit the milk, so that the liquid milk into the air, using the surface tension of milk protein around to form a lot of small foam, so that the liquid milk volume expansion, into a foam-like milk bubble. In the process of foaming, lactose dissolves in milk because of the increase in temperature, and uses the role of foaming to seal lactose in milk bubbles, while the function of milk fat is to make these small foams form a stable state, so that when these milk bubbles are drunk, the fine foam will burst in the mouth, so that the taste and aromatic substances have a better magnifying effect, so that the milk produces sweet and thick taste and taste. And in the fusion with coffee, the adhesion between the molecules will be relatively strong, so that the special properties of coffee and milk are highlighted respectively, and completely fused together to complement each other.

b. Make dense and meticulous milk foam

When we make good milk foam tissue, there are many different ways, but they all include two stages: the first stage is to get rid of, that is, to put in steam to make the volume of milk foaming, and the second stage is to beat the foamed milk, which involves the foaming milk into the air by means of a whirlpool, and breaks the larger milk bubbles, breaks them into fine foams, and makes the milk molecules bond with each other. Make the foam tissue more compact.

There are many ways of foaming milk on the market, but they are roughly divided into two categories: one is the combination of milk and milk foam, and the other is to separate the stages of milk foam and milk foam. that is, first beat the milk and then beat the milk foam. The milk bubble tissue formed by these two ways is different from the taste. In the first way, the milk bubble tissue will be more delicate and soft, but the texture of the milk bubble will be thinner and less likely to produce dense and elastic milk bubble tissue. But the round shape of the flower is easier to form. The second way is to send the milk first and then the milk foam. The milk foam tissue produced in this way has a high degree of silk, which can produce QQ elastic milk foam, but it is easier to produce thicker milk foam tissue in the passing stage, and it will be more difficult to make the pattern of pull flowers, but the taste of the brewed coffee will be more dense.

Six factors affecting milk bubbles

a. Milk temperature: milk temperature is a very important factor when dispelling milk. When the storage temperature of milk increases by 2 ℃, the shelf life of milk will be reduced by half, and the higher the temperature, the more milk fat will decompose and the lower the degree of foaming. When the milk is foaming, the lower the initial temperature is, the more complete and uniform the protein denaturation is, and the higher the degree of foaming is. In addition, it should be noted that the best storage temperature of milk is about 4 ℃.

b. Milk fat: generally speaking, the higher the composition of milk fat, the denser the tissue of milk bubbles, but the proportion of milk bubbles will be less, so, if all use full-fat milk with high milk fat, the milk foam tissue may not be the best state. Excessive addition of some foamed ice milk, milk foam tissue and the amount of milk bubbles, will be more and dense taste.

c. Steam pipe form: the outgassing mode of the steam pipe is mainly divided into two types: the transverse type and the centralized type. Different forms of steam pipe, the outgassing intensity and outgassing volume will be different, coupled with the change of the position of the outlet hole and the number of holes, it will cause the difference between the angle and the way when milking. On the other hand, the expanded steam pipe should not be too close to the edge of the steel cup to avoid turbulence, while the centralized steam pipe should pay more attention to the control of the angle, otherwise it is easy not to produce good foam tissue.

d. Steam size: the greater the amount of steam, the faster the speed of milk, but relatively easy to have thicker milk bubbles, large steam way, but also more suitable for larger steel cups, too small steel cups are easy to produce turbulence phenomenon. The small amount of steam pipe, milk foaming effect is poor, but the advantage is not easy to produce thick bubbles, play for a long time, the overall control will be easier.

e. Steam dryness: the higher the dryness of the steam, the lower the water content, and the milk bubbles will be denser and less moisture, so the dryness of the steam is better.

f. The size of the steel cup shape: the size of the steel cup is related to the type of coffee drink to be brewed, the larger the cup, the bigger the steel cup. Generally speaking, the pig cappuccino uses the steel cup with 600ml capacity, while the latte coffee uses the steel cup with 1000ml capacity. Use the correct steel cup capacity to produce well-organized milk bubbles. As it is the way of making coffee flowers, the shapes of steel cups are mainly sharp-mouthed, while different sharp-beaked steel cups need to rely on their own more practice.

The fusion principle and fusion mode of coffee and milk foam

The principle of fusion: the fusion of coffee and milk is a very important step in brewing espresso. It can enhance the taste and taste of espresso to a better level, and can also fix the small errors that occur in the process of making espresso and milk foaming, and change the taste of the whole cup of coffee through fusion methods and techniques. What is the principle of integration? First of all, we use our imagination to imagine coffee, milk and milk bubbles as a molecular state, and the best way to fuse is that the whole cup of coffee is a uniform molecular combination of coffee, milk and milk bubbles. To achieve this level, we must give the binding force between molecules during fusion, and such forces must be stable and continuous. Therefore, in the fusion, milk and milk foam molecules should be poured in a quantitative way to make a uniform combination of coffee, milk and milk foam molecules, so that when we drink the whole cup of espresso, each mouthful is a uniform molecular combination of coffee, milk and milk foam, so as to give full play to the effect of each molecule and make the whole cup of coffee show the best state.

One of the ways of fusion

1. Fusion action coffee first put the steel cup close to the edge of the cup, pour into the amount of milk foam should not be too much, lest the initial impact force is too big to break up the surface cream.

two。 Then raise the steel cup and add more milk foam to increase the strength of fusion.

3. Then reduce the height of the steel cup and control the flow of milk foam to make the fusion strength uniform.

4. Then raise the steel cup to do the second fusion action.

5. Finally, lower the height of the steel cup to the edge of the cup, wait until the cup is full and quickly remove the foam.

Fusion technique: before mixing coffee and milk foam, we must scrape off the thicker milk foam from the surface of the foamed milk foam with a stainless steel spoon, and pay special attention to the gesture of holding the spoon with fingers on the back of the spoon to avoid scooping up the painstaking milk foam.