Does the strength of the powder have an effect on the extraction of espresso? How hard does it take to make Italian coffee?

Pressing pressed powder with a powder hammer is a critical step in the extraction of espresso. In the past, the focus of the discussion on pressing powder is how to flatten it. Because when the pressure is uneven, it is easy to produce uneven extraction.

As for whether the strength of the powder will affect the extraction of espresso, we also have different views. Some baristas will think that the strength of the powder should be controlled properly, and too much force will press the coffee powder too hard and slow down the flow rate. Some baristas think that as long as you make sure it is flat, it doesn't matter how much pressure you use, because the strength of manual filling is not worth mentioning in front of the pressure of coffee machine extraction.

Qianjie has also done experiments on the strength of powder pressing. The current street uses a Galileo bean grinder to grind 18.5g coffee powder, press the powder with the strength of 1.8kg after the cloth, and extract 37g coffee liquid in 27 seconds.

Using the same grinding scale, the same amount of powder, using the strength of 9kg to press the powder, it took 36 seconds to extract 37g coffee liquid, the flow rate was significantly slower, and the effluent time was significantly slower by 2-3 seconds.

But adjust the grinding degree to 2.2g, grind 19.5g coffee powder, press the powder with the strength of 1.8kg after the cloth, and extract 39g coffee liquid, which takes 28 seconds.

It is also suitable for 2.2g coffee powder and 19.5g coffee powder. Use the strength of 9kg to press the powder after the cloth, and extract 39g coffee liquid, which also takes 28 seconds.

The two also use two different forces, but there are no different results, which is due to the difference in density caused by the fineness of coffee powder.

In the previous group of tests, the grinding degree of coffee chose a finer grade, while the difference in the strength of the powder makes the density of pressed powder inconsistent, using 1.8kg strength, pressed powder is relatively less solid, pressed powder has a relatively low density, so the flow rate is faster. The strength of the use of 9kg, pressed powder pressure is relatively strong, so the flow rate is relatively slow.

In a group of tests with coarse coffee grindness, no matter how much pressure is used, the gap between coffee powder particles in pressed powder is bound to be larger than the previous group. Both the strength of 1.8kg and the strength of 9kg have actually been pressed to the fullest. Therefore, the flow rate and time of the coffee extracted by the two forces are similar, and it does not have much impact.