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What is the channel effect of coffee? Why does espresso have a channel effect? What is the reason? How to solve it?

Published: 2026-08-25 Author:

Last Updated: 2026/08/25, The term "channel effect" is often mentioned in articles on the front street, because during the extraction process of coffee, the generation of channel effects will have a certain negative impact on the taste of coffee. And its trigger frequency is not low! So today Qianjie will come to share with you what this channel effect is! It should be as follows

The word "channel effect" is often mentioned in Qianjie articles, because in the process of coffee extraction, the generation of channel effect will have a negative impact on the taste of coffee. And its trigger frequency is not low! So today Qianjie will come to share with you what this channel effect is! And how to prevent the emergence of channel effect.

What is the channel effect? The channel effect in coffee refers to the uneven distribution of hot water in the process of extraction. If we want to get a delicious cup of coffee, in addition to ensuring the stability of the parameters, we also need to let the hot water permeate most of the coffee powder evenly, so that the coffee powder can release the right amount of flavor substances.

In an ideal state, the water will be affected by gravity and actively infiltrate downward, so that the coffee powder is extracted evenly. However, with inert water, it will give priority to finding a place where it is easy to flow and concentrate to seep out. What do you mean? For example, if we want to water a dry piece of land, and there is a crack in the land, then the water will concentrate on infiltrating into the crack. As long as this truth is converted to the hot water extraction of coffee, it will be easy to understand!

This will then lead to ultra-efficient extraction of places where the water is concentrated, dissolving smelly substances that should not have been dissolved! On the other hand, where there is not concentrated extraction by water, there is a lack of extraction, that is, the amount of dissolved substances is not enough, and then these unsaturated coffee liquid will affect the whole cup of coffee, resulting in a lack of concentration and taste. The most affected by the channel effect is the extraction of espresso! Because Italian extraction requires hot water to dissolve 2/3 of the soluble matter of pressed powder in a very short time, the extraction efficiency of all parameters is very high. If there is a channel effect in this extreme environment, it will have a great impact on the taste of coffee.

Although we can't look directly at the flow of hot water during extraction, it doesn't matter. Because the performance of the channel effect is very obvious after it is produced. Even if you haven't tasted the coffee yet, you can tell whether the channel effect occurs from the following conditions.

The reasons for the channel effect caused by the holes in pressed powder are the uneven distribution of coffee powder in pressed powder and the inconsistent flow resistance in various fields of pressed powder, which leads to a breakthrough in the concentration of hot water in a place with weak resistance. So when the channel effect occurs in the process of extraction, we will see not a small number of dense holes on the surface of the unloaded pressed powder, which are the "channels" through which hot water runs through. And "perforation" is what we call this phenomenon.

Second, the use of sputtering bottomless handle during extraction can help us to see this phenomenon more intuitively, because bottomless handle is invented for this purpose. Therefore, if we use bottomless handle for extraction, as long as there is a channel effect in the process of extraction, there will be a probability of sputtering in the process of concentration, as shown in the following figure.

How to solve the channel effect? Since it is mainly the distribution of coffee powder, we only need to optimize the distribution of coffee powder. Qianjie in the "the importance of reasonable cloth powder" this article has a detailed description of the details of the cloth powder link need to pay attention to, you can directly click on the blue font to jump to explain.

Finally, Qianjie suggests that people wearing light-colored clothes had better keep a certain distance in the extraction process of bottomless handle, otherwise, the channel effect will not only make the concentrated taste "mixed" ~

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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 。