This article will explain the main mistake or problem when preparing espresso. To achieve a perfect espresso, you must follow many steps and understand the theory very well; that’s why espresso extraction is the most complicated of all extraction techniques.
If you cannot extract a good espresso, even if you have the ideal equipment and quality coffee beans, this information will be very useful. There are many reasons one can extract a perfect espresso, but today I will talk about channeling, one of the most important.
In all my articles, I emphasize the importance of obtaining an even and uniform extraction with any of the methods I use, this is what will guarantee a good final flavor of the coffee.
If there are parts of the coffee bed where the water can pass more easily, an extraction flow will be created in that area, dissolving more soluble solids than the rest. This is known as channeling and results in espresso with unbalanced flavors.
Several situations can cause this channeling problem; below; I will detail each one of them:
Canalization caused by a bad dosage
Depending on the grinder you use, if you leave the portafilter fixed in the same place, the coffee accumulates in only one part of the basket. No matter how much we want to correct it later with our finger or with some utensil, we will only be moving the surface, and the bottom will continue to be uneven.
Then when we proceed to sift, the coffee will be much more compact in that area, and there will be a channel on the opposite side where the water can pass much more easily.
I move the portafilter as the coffee is falling, and this way, I make sure that the dosage is evenly distributed. Then I tap it a few times, so there are no air bubbles.
Channeling caused by a bad tamping
Even if you distribute the coffee perfectly when dosing, if the tamper is not perpendicular to the portafilter, it will compact one side more than the other. This cannot be corrected by moving the tamper to the other side, so always check the position and tamper only once.
Channeling caused by knocks on the filter holder
The third scenario where channeling can occur is when after dosing and uniform sifting, for some reason, we hit the portafilter, either unintentionally with the tamper or when placing and adjusting it in the machine.
This can cause the coffee pod to break or detach from the basket’s walls, causing the water to pass through these places without extracting the coffee uniformly.
How to identify espresso channeling?
The problem with the channeling is that we cannot identify it simply by looking at the coffee pod. Even after sieving a bad distribution, the coffee looks perfectly level. This is why you must closely consider all the steps, considering what can happen inside.
Sometimes we can diagnose it at the moment of extraction; by observing the espresso outflow, we can see that it comes out faster on one side than the other or also see bubbles coming out of the portafilter.
Channeling is a problem that happens to everyone when starting in the espresso world, so it is something to pay attention to.
Sometimes we focus too much on the calibration or the recipe and get frustrated when we don’t get a good result. So I hope you find this information useful and put it into practice.