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What should I do if the powder sticks to the coffee maker? What is the use of the pressure relief function of the coffee maker? Why does the espresso machine know how to fry it?

Published: 2026-04-26 Author:

Last Updated: 2026/04/26, I don't know if my friends have encountered this situation: when we finished extracting the espresso, we took off the handle and buckled it on the powder residue bucket. As a result, there was no expected sound of the powder cake falling from the powder residue bucket. Looking back, I found that the powder cake was attached to the brewing head of the coffee machine. And in the coffee ring, such a situation occurs

I wonder if my friends have ever encountered this situation: when we took off the handle and buckled it on the powder bucket after we had extracted the espresso, there was no expected sound of pressed powder falling from the powder bucket. Looking back, I found that pressed powder was adsorbed on the brewing head of the coffee machine.

In the coffee circle, such a situation is not pleasant, and is even classified by many baristas as "one of the" nightmares "in the process of work. Then the question arises: why is pressed powder attached to the coffee machine after the extraction is completed? And why is the emergence of such a situation so unpleasant? Listen to Qianjie and explain it online!

Why is pressed powder attached to the coffee machine? It is well known that Italian coffee machines are basically equipped with a pressure relief function to remove the pressure from the powder bowl after the extraction of espresso is completed. In this way, the phenomenon of blowing up the plane will not occur due to the existence of pressure when we take off the handle (as shown in the figure below).

That pressure relief will also produce a suction, which will take away the hot water left in the powder bowl. And it is this force that causes pressed powder to stick to the head. Under normal operation, the suction produced by the pressure relief is not enough to cause pressed powder to be adsorbed on the cooking head. If we see pressed powder adsorbed on the watershed, it means that we may be using a little too much coffee powder.

The reason why part of the water remains in the powder bowl when the coffee extraction is completed is that there is a certain distance between the normal pressed powder and the water diversion network under the recommended amount of powder, that is, a blank space. The existence of this part of the space is destined to mean that when we end the extraction, some of the hot water will remain in the powder bowl because the coffee machine stops pressurizing and cannot seep out. But when we fill too much powder, this part of the space will be reduced, and then the distance between pressed powder and the water diversion network will be shortened. Naturally, there is less hot water left in the powder bowl at the end of the extraction. Then when the suction produced by pressure relief can not absorb the hot water, it will begin to act on pressed powder. This situation is the main reason for pressed powder adsorption on the water diversion network, and then on this basis, there are two other factors will increase the trigger probability of pressed powder adsorption. One is that when the coffee powder is filled too much, the handle is not removed for a long time after the extraction is completed. The pressed powder that was originally attached to the watershed may be shocked back into the powder bowl when we disassemble it, but if we do not remove the handle for a long time, then the pressed powder that is already glued to the watershed will be dried and absorbed more firmly.

There is also a situation where we hit the handle after filling the coffee powder! Tapping the handle will create a gap between the pressed powder originally filled in the powder bowl and the powder bowl, not only will it be more easily adsorbed on the coffee machine after the extraction is completed, but also more likely to produce a channel effect in the process of coffee extraction. and then affect the flavor of the coffee. So in this case, it is necessary for us to pay attention to the action after filling the powder bowl to avoid the uneven extraction taste of the coffee.

What is the negative impact of the adsorption of pressed powder on the powder water network? Except for the channel effect triggered by the last case mentioned, none of the other reasons will affect the extraction of coffee, so we don't need to worry too much (instead, it is a proof that the coffee machine is working properly). And the reason why this situation is not pleasant, mainly because many times, coffee people find that the opportunity of pressed powder is not to lean down to see pressed powder on the brewing head, but the sound of pressed powder falling from the brewing head to the sink because of the weakening of adhesion.

If it is connected to the sink like the coffee maker on the front street, it will be a lot of trouble for the pressed powder to be cleaned. It's hot! It's strange to be able to please! -END-

FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou China, selling freshly roasted beans from its own farm in Yunnan as well as dozens of carefully selected single-origin beans from around the world for both pour-over and espresso. The products deliver consistently excellent quality and great value, with shipping within 24 hours. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers, and the beans are now available online at the Tmall 。