Key points of espresso production: how tight the cloth powder and the pressed coffee powder should be pressed.

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

Cloth powder

Cloth powder is the process of putting the ground coffee powder into a powder bowl and distributing it evenly. The successful distribution standard of coffee powder is to make coffee powder evenly distributed, so that some areas will not be overextracted or underextracted during extraction.

When you put the coffee powder into the powder bowl, the powder will be piled like a hill in the middle, usually more in the middle and less around. In the extraction, due to the inertia of the water, the flow of water will be easier to pass through the middle, so in theory, the amount of powder in the middle of the powder bowl should be more than four weeks.

However, because the powder bowl structure of the double-headed handle is different from that of the single-headed handle, we need to treat it differently.

IMG_9473

The middle of the handle itself is deeper than four weeks, so when filled with coffee powder, we use the tiger mouth of our hand or the lid of the grinder to smooth out the excess coffee powder and fill the gap in it at the same time. In this way, the amount of powder in the middle part will naturally be more than that around (at this point, some people will scrape off the middle part with the powder cartridge cover to make it sunken, so that if it is scraped off too much. On the contrary, it will cause uneven extraction.

Because the overall depth of the double-headed handle is the same, we need to increase the amount of powder in the middle when loading the powder, that is, to keep the shape of the hill moderately.

In addition, many people, whether after loading the powder or after pressing the powder, like to hit the four sides of the powder bowl with a powder hammer, which is actually a mistake, especially after pressing the powder, it is easy to cause the compacted pressed powder to be loose. on the contrary, it will cause uneven extraction.

Pressing powder

There are all kinds of theories about the strength of powder pressing, 5 pounds, 10 pounds, 20 pounds. Few people know what it is, and there's no need to worry about how many pounds of force it takes, just remember to apply the force evenly so that the pressed powder's tight surface is smooth.

If the force is too heavy, the water flow during extraction will be very difficult to pass pressed powder, and it is easy to cause insufficient extraction, while too little force will cause excessive extraction, so the powder pressing strength is not the bigger the better, nor the smaller the better. This needs to be constantly tested and adjusted.

How much force you have to use to feel it, after all, the strength of the powder should be the freest parameter in the gold extraction rule.

IMG_9475

Extraction

Then come to the extraction part, put the handle on the head of the coffee machine, press the extraction key and wait. The only thing you need to do is seize the time.

According to the definition of "EspressoCoffee The Chemistry of Quality", it must meet the following conditions:

Coffee powder (cup) 6.5 ±1.58g water temperature (℃) 90 °±5 °water pressure 9 ±2 atmospheric pressure (bar) filtration time 30 ±5 seconds

Excessive coffee powder extraction; excessive coffee powder; too fine powder; too small pressing power; too high temperature.

Insufficient extraction; insufficient coffee; coffee powder is too coarse; pressing power is too strong; coffee machine temperature is not enough.