Espresso extraction-the difference between American and Italian concentrate

Espresso extraction-the difference between American and Italian concentrate

Italian coffee machine uses pump to generate pressure, which is roughly divided into shock type and rotary type. Vibrating type is compact in size and low in cost, which is mostly used in household machines, such as XX coffee machine, pump pressure 15bar or pump pressure 19bar, which means that the peak pump pressure can reach 15bar or 19bar, but does not stabilize in a single value, but fluctuates between 1--15bar. This is also one of the reasons why the coffee made by household machines has a lot of miscellaneous flavor. Similarly, this is another basis that I do not think the cone knife grinder can bring a deep flavor, because if this logic is true, the unstable pressure of the vibration pump will also bring different levels of flavor. The lower the controllability in brewing, the worse the taste stability.

The rotary pump is mainly used in commercial machines and high-end professional household machines because of its large size. The pressure can be stabilized within a fixed value, from a straight point of view, the pressure curve of the vibrating pump is fluctuating, while the pressure curve of the rotary pump tends to be a straight line, the two are not the same. The use of rotary pump is a major element of stable extraction. In addition, the noise of rotary pump is much lower than that of vibrating pump, and some vibrating pump noise makes people feel unsafe and cheap, and noise can also affect people's mood, so it is not recommended to use vibrating pump coffee machine as a business machine.

At present, the standard of esp brewing theory is 9 ±1 and 9 ±0.5,9 ±2 respectively. Here in order to facilitate the memory and understanding of the individual is set at 9. Water temperature control of most household machines due to the use of heating blocks or smaller boiler water temperature is difficult to stabilize, in the process of extraction, the temperature difference can be up to 10 degrees deviation, even if the operator is more careful, can not overcome this hardware bottleneck. And large-scale mainstream commercial machines (heat exchange type) also have a temperature difference of 4-8 degrees, so there are considerable requirements for the operator's control. For coffee machines with independent PID temperature control in double boilers and multi-boiler systems, it is relatively easy to stabilize the temperature. The Aibao twin boilers I use can make the temperature difference of a cup of esp extraction only 0.5 degrees Celsius. Higher-end coffee machines such as synesso, slayer, etc., can control the temperature within 0.1C, while the resolution limit of human taste for temperature effect is about 0.3C. So 0.1 degree temperature control is perfect for human beings.