Coffee machine recommended guide for the purchase of household coffee equipment

The best pressure used to extract espresso should be 9bar. But where does this pressure come from? Some people will say, there is no doubt that it must be a water pump! When the pump water is pressurized, it naturally becomes pressure water. This is the pressure used to extract coffee. This is a concept when many people who don't know anything about coffee machines buy coffee machines. But in fact, it is not so simple, the pump pressure is not equal to the pressure of extracting coffee. During the operation of the machine, the pump only plays the role of "transporting" water from the water tank or water source to the heating source, and then "transporting" to the boiling head. The pressure of coffee extraction is due to the resistance of coffee powder. If no powder bowl is added, the water will come out of the brewing head and communicate directly with the atmosphere, so there is no pressure. Only by blocking the end of the cooking head can the water form pressure on the inside. When the size and strength of your coffee powder are right, you can withstand the pressure of 9bar. At this time, the pressure in the powder bowl is 9bar. Therefore, the pump pressure does not have much effect on the extraction of coffee, whether it is 15bar or 19bar, will not directly affect the extraction. The so-called 15bar and 19bar are only the limit of the pressure generated by the pump. To put it another way, when the resistance at the head end of the coffee machine can withstand this peak, the pump of the coffee machine will stop pumping, but many pumps will stop pumping when they reach the value of 13bar. 15bar and 19bar, or the magnitude of the pump pressure, can make a difference in your extraction because of the difference in pressure, the difference in the flow rate of water, which affects your extraction time, that's all, and that's not enough to change the taste of your coffee. So from this point of view, as long as the pump pressure is above 9bar, you can make a passable cup of espresso. Pump pressure does not directly affect the quality of your coffee.

Most household machines in the market use ULKA pumps, and the domestic cost is about 50 yuan.

Another point I would like to mention here is that many low-end household phones, such as the Cankun 1817, use pressurized worry bowls. The so-called pressurized worry bowl is a double-layer worry bowl. The first layer is a normal filter screen with many small holes, and the second layer filter net has only a very small hole. Under the action of this kind of worry bowl, even if there is no coffee powder in the powder bowl, because there is only one small hole, it can reduce the flow rate of water and form at least 5bar pressure in the powder bowl. If you fill the coffee powder again, as long as you fill it gently, you can easily get considerable pressure, so it is easy to make espresso oil by using household machines such as 1817. The pressurized filter screen plays a role in avoiding some disadvantages of hand pressure, making it easy for beginners to make a passable cup of espresso.