The knowledge of espresso should be paid attention to in making espresso.

1. Italian professional coffee maker

According to the cooking and heating system of the boiler, it is generally divided into four types, namely, single boiler system, sub-master boiler system, double boiler system and multi-boiler system. Four different boiler brewing and heating systems will be different when we brew espresso, and the main reason for the difference comes from the different configuration of the boiler and the heating mode of the heater.

Single boiler system: the hot water, steam and water of the single boiler system are all heated by the same heater. When using a single boiler system to brew coffee, the outlet temperature of the flushing head will be directly affected by the use of hot water and steam. And the situation is unstable, so the way of the single boiler system is mostly used on the household coffee machine or lever spring piston coffee machine. General commercial espresso machines no longer use this system.

The sub-master boiler system: the hot water and steam of the sub-master boiler system are heated by the same heater as the water used in the brewing head, but the heating of the sub-master boiler is heated by heat exchange with the parent boiler, and when using the sub-master boiler system to brew coffee, it does not directly make the outlet temperature of the flushing head receive a large temperature to lower the outlet temperature of the flushing head, while the brewing mode of the parent boiler system It is the boiler system of most espresso machines on the market, so the stability of the machine is within an acceptable range without using a lot of hot water.

Double boiler system: the hot water and steam of the double boiler system are heated by the same heater, and the water used in the brewing head is heated by another heater. When using the double boiler system to brew coffee, the outlet temperature of the brewing head will not be reduced because of the use of steam and hot water, and the stability of the machine is good.

Multi-boiler system: the heating mode of the multi-boiler system is very similar to that of the double-boiler system, except that each head has its own independent heater, which can set the water temperature, so the Italian coffee machine with double head has three boilers. The Italian coffee machine with three boilers has four boilers.

Each kind of boiler system has its own characteristics and differences. When choosing an Italian coffee maker, we should consider several points.

a. Is the ease of operation good?

b. Whether all the control buttons and knobs respond well

c. Is the stability of the machine good?

d. Whether the reheating speed is good or not

e. Is the steam outgassing enough?

f. Is the dryness of steam good?

two。 Steam pipe, nozzle

Each Italian coffee machine uses a different form of steam pipe and the outlet mode of the nozzle. From the form of steam pipe, it is divided into long tube type and short tube type, and it is divided into thick tube type and thin tube type. When the long tube type is in use, the steam strength of the long tube type is weaker than that of the short tube type, but the long tube type is not easy to be restricted in operation. The gas output of the steam pipe of the thick tube type is larger and the strength is weaker than that of the thin tube type, while the gas output of the thin tube type is small and the strength is stronger.

The outgassing mode of the nozzle head has a lot to do with the arrangement and position of the outlet holes, most of the outlet holes are 4 holes and 5 holes, and different arrangement positions will cause different outlet directions, so it can be divided into two types: the lateral expansion type and the centralized type.

Different forms of steam pipe, the outgassing intensity and outgassing volume will be different, coupled with the different position of the outlet hole and the number of holes, it will cause differences in the angle and way of milking. Before using the Italian coffee machine, you should pay attention to the form of the steam pipe used, together with the appropriate milk, so that you can make dense and fine milk bubbles.

3. Selection of bean grinder

Generally speaking, the professional bean grinders in the market use disc cutting to grind coffee beans, while household bean grinders mostly use blade type to grind coffee beans, and use chopping beans to grind coffee beans. the uniformity of coffee powder after grinding is very different between the two. Although the price of the disc grinder is expensive, it has a great influence on the control of brewing coffee. Therefore, it is suggested that we should take the disc-cutting bean grinder as the first choice.

The professional disc cutting bean grinder, distinguished by the form of blade, is divided into two types: disc blade and conical blade, most of which mainly use disc blade, that is, upper and lower cutters. the lower cutter plate uses motor rotation to drive rotation to achieve the role of grinding coffee beans, and to rotate the upper cutter head to adjust the distance between the upper and lower blades to control the size of coffee powder. The size of the flat cutter head, the diameter is the most common in 58mm, 64mm, 75 ┨, 84 ┨. The larger the diameter of the cutter head is, not only the speed is faster, but also the grinding is more uniform, and the production of heat energy is smaller, which can ensure that the aromatic substances of coffee powder will not be lost too much. In addition, it should be noted that the spacing when rotating the cutter head to adjust the scale should not be too large, lest it is impossible to adjust the thickness of coffee powder slightly. In addition, some bean grinding machines have counterweight ways to grind coffee beans because of the vibration when grinding coffee beans, resulting in uneven grinding of coffee beans, so we can choose a good professional bean grinder according to the above key points. this has a very critical impact on the quality of professional coffee.

4. Coffee powder filling machine

There are many different types of coffee powder fillers on the market, but generally speaking, they are mainly divided into two types: plane type and arc surface type. As for the difference in material and weight, it varies according to individual habits and methods. We won't discuss it here. So how to choose the plane type and the arc type fillers? Before choosing, we should first pay attention to the Italian coffee machine brewing head filter, with the shape of the filter cup on the filter handle, flat filter and filter cup, with flat coffee powder filler, arc-type filter and filter cup, with arc-shaped coffee powder filler, so that the filled coffee pressed powder can be uniformly combined with the filter and filter after absorbing water and expanding, so that coffee pressed powder can be extracted evenly. Otherwise, it will cause the uneven density of coffee pressed powder after water absorption and expansion, so that the coffee will be over-extracted or underextracted, so it is very important to choose the appropriate coffee powder filler.

5. Brushed steel cup

There are also many types of drawn steel cups, according to the shape of the steel cup mouth is mainly divided into two types, sharp mouth type and round mouth type, sharp mouth type steel cup is easier to draw thin lines of the circle, round mouth type is easier to draw symmetrical patterns. According to the form of steel cup mouth groove, it can be divided into long groove type and short groove type. the longer the groove shape is, the better the function of collecting milk is, and it is better to control it when drawing patterns, while the short groove is better to use when scraping milk bubbles. In addition, the grip form is also divided into connection type and separation type, the grip of the connected type steel cup is better mastered, and the separated type steel cup is better used in chilled cooling. As for what kind of steel cup works well? In fact, as long as you are proficient in habits, so more practice is the key to success.

Other utensils include thermometers, stainless steel spoons, hand-held milk foam pots, stainless steel pots, stainless steel cups, Italian grinder coffee pots, electric or gas stoves, toothpicks, needles, screens, etc.

Materials that determine quality

1. Italian coffee beans

There are many kinds of Italian coffee beans on the market. Italian coffee beans are blended in the way of comprehensive beans because of their rich and multi-layered taste and taste. And Italian coffee is also divided into southern Italian flavor coffee and northern Italian flavor coffee, the northern Italian beans are roasted in medium and shallow way, due to the selection of beans, the caffeine content is less, the taste is rich and bright with a little sour fruit flavor, and the aroma tends to flower or peel aroma. Nanyi coffee beans are deep-roasted because of their high caffeine, full-bodied flavor and caramel-like sweet finish, with a fruity or cocoa aroma.

Why is there such a difference between the North and the South? Because Italy is a long country, there is a great difference in climate between the north and the south. Because the climate is cold and the taste of the diet is relatively light in the north, most of the coffee beans are roasted in the medium and shallow way, while those in the south are mostly roasted because of the hot climate. So the taste of the diet is heavier, and naturally the roasting of coffee beans tends to be heavy. In addition, because of the gap between the rich and the poor in North and South Italy, when people in northern Italy choose coffee beans, the proportion of Arabica beans is higher, because the content of caffeine will be lower, and the content of coffee oil will be relatively less. And people in southern Italy will add Robusta beans when matching beans, so that the content of caffeine will be more than the flavor of Northern Italy, so the content of coffee oil will be more abundant.

two。 milk

Generally speaking, whole milk is more appropriate when choosing milk, and milk fat above 3% is more suitable, while the taste, organization and composition of various brands are slightly different, and they are paired with coffee beans according to their personal preferences. If Italian coffee beans choose southern Italian flavor, then you can choose milk flavor when choosing milk, but if you want to emphasize the flavor of coffee You can also choose milk with ordinary milk flavor. If Italian coffee beans choose northern Italian flavor, you can choose medium milk flavor when choosing milk, so that the flavor of coffee will not be changed by milk, but if you want to put special emphasis on the flavor of milk, you can also choose milk with strong milk flavor, according to your own needs and preferences.

3. Other materials include cocoa powder, cinnamon powder, chocolate sauce, caramel sauce and so on.

Coffee cups and flowers

The shape of the coffee cup is also closely related to the way the flower is drawn. Generally speaking, the shape of the cup body is divided into two categories, one is the tall cup, the other is the short cup. Tall cups are longer and stronger. But if the amount of milk foam is not enough, it will not be enough when you start to draw a flower pattern, and you will not be able to draw a beautiful pattern. On the other hand, if the amount of milk foam is very rich, the coffee pattern will be very good, but the skill will also be relatively improved. Because the dwarf cup has less capacity and shallow depth, the action of drawing flowers should be very fast, and it will be more difficult to make advanced patterns and difficult patterns, but the pattern will be easier to appear when brewing coffee.

In addition, the shape of the bottom of the cup is also very important, which can be roughly divided into two types: the arc bottom and the square bottom. the fusion uniformity of the arc bottom will be better than that of the square bottom. the reason for this is that the surface area of the square bottom is larger and the height of espresso will be reduced, so it is easier to overturn during fusion, resulting in the breaking of the cream on the surface. And the shape of the square bottom right angle will also make the tumbling way not smooth during the fusion, and the fusion is also easy to produce uneven situation, so that the taste is not uniform, and even the diameter of the cup mouth will have a different effect. The larger the diameter of the cup mouth, the larger and brighter the pattern, but because the larger the diameter is, the larger the surface area is, and the thickness of the milk bubble will be affected and reduced. However, if the diameter of the cup mouth is too small, it will be more difficult to pull flowers.

Finally, when choosing a cup, you should choose a cup with a better heat preservation effect, so as to maintain the temperature of the coffee.

The key to the success of Coffee blossoms

Coffee-- Adjustment and setting of machines and equipment

1. Italian professional coffee maker

a. Boiler pressure

Boiler pressure gauge: the realistic unit of the boiler pressure gauge is bar, that is, the unit of atmospheric pressure, which is generally adjusted at 1 ±0.2bar. Some boiler pressure gauges and water pressure gauges are displayed in the same pressure gauge, which are configured for the upper and lower parts and left and right respectively. The easiest way to identify is that the measurement scale of the boiler pressure gauge is small, and the pointer does not change much when brewing coffee.

Boiler pressure adjustment box: most Italian coffee machine boiler pressure adjustment box is the same, only a small number of brands will use their own parts as adjustment, or use computer board settings, so, now we will introduce the general way. There are two adjusting screws on the boiler pressure adjustment box, one is the fixing screw and the other is the adjusting screw. When making the adjustment, you should first loosen the fixing screw, and then rotate the adjusting screw to adjust. Most of the adjustment directions are clockwise to reduce the pressure, counterclockwise to increase the pressure, and then tighten the fixing screw when adjusted to the set pressure value.

b. Cooking pressure

Brewing pressure gauge: the display unit of the brewing pressure gauge is also bar, which is generally adjusted to 9 ±2bar. When the brewing pressure gauge has not yet begun to brew coffee, the pressure displayed is the water pressure of the inlet pipe itself, usually about 1-2bar. After pressing the brewing switch, it will show the pressure of setting, and pay special attention to one thing: when you set the brewing pressure, you need to fill the brewing handle with coffee powder. This setting of cooking pressure is correct, because the pressure on coffee powder will be greater than when there is no coffee powder, so pay special attention to this.

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 make foamy milk, which involves the foaming milk into the air in a whirlpool way, and breaks down the larger milk bubbles and decomposes them into small foams. And let the milk molecules have the role of bonding, so that the foam tissue becomes more dense.

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.

In the fusion process of coffee and milk foam, the most important skill is to maintain a certain flow of milk foam to merge with the coffee, and give the appropriate fusion strength. When we pour into the milk bubble, the steel cup must continue to move up and down to give fusion strength, but to maintain the injection of a certain amount of milk foam, the steel cup must increase the amount of milk foam when it rises, so the wrist must control the amount of milk foam poured in. When the steel cup falls, the amount of milk foam must be reduced, and the wrist must control the amount of milk foam poured in, and the foam must be poured continuously instead of intermittently in the process. Therefore, the part of the elbow should be slowly improved at a fixed speed, and this skill must be constantly practiced before it can be used skillfully. We can use the flow rate when pouring into the foam and the impact force during the fusion to change the concentration and taste of the coffee. The greater the impact force and flow rate of the fusion, the lighter the coffee concentration taste, and the smaller the impact force and flow rate of the fusion, the stronger the coffee concentration taste, so that the taste of different concentrations can be adjusted to meet the needs of different customers.

Speed and rhythm of fusion: there is also a very important factor in fusion, that is, the speed and rhythm of the fusion of coffee and milk foam. The speed of fusion will affect the taste of the coffee, while the rhythm will affect the overall performance of a cup of coffee and the pattern of flower drawing. In the fast and sometimes fast, the slow sometimes slow, in which the rhythm must have the accumulation of skilled skills and experience, and different patterns will have different rhythms.