How to reduce the channel effect of espresso extraction? What is the difference between pressing powder and cloth powder?

Making espresso is a very healing process, whether it is the smooth flour after the cloth powder and the golden oil slowly flowing out during extraction, it can make us feel comfortable. Qianjie believes that after the concentrated extraction is finished, the moment when the complete pressed powder is withheld by the handle is the most comfortable ~ it only needs a gentle "slap"! A complete piece of pressed powder can be shown. But often, some friends can't get a complete pressed powder. For example, after pressed powder is deducted, it looks like the following picture:

Not only is pressed powder fragmented, but even espresso doesn't taste so good. I can't help thinking, is there some kind of connection between the two?

Don't tell me, there is! But it is not to say that pressed powder is not lumped does not mean that the concentrate is not delicious, but because some factors lead to pressed powder not clumping, there is a gap in extraction, and the final espresso is not so delicious. Just like when you hit pressed powder too hard, it will also be torn apart by too much impact. The main reason why pressed powder is not agglomerated and concentrated is the channel effect during extraction. The appearance of this kind of pressed powder is often with characteristics, such as the surface will have small holes, that is, we often say "perforation".

In addition to the holes on the surface, pressed powder, which produces channel effect, will have other characteristics. For example, pressed powder has two very different colors. Just like the pressed powder at the beginning, I don't know if you have noticed, it has two completely different colors. Looking at the lighter places, we can see that the coffee particles that make up these places are all dry. These are symbols of the channel effect, and hot water flows out of other places, and this part is not extracted, so they are not coagulant. So it can't be lumped, and the coffee isn't that good.

And the solution to this problem is also very simple, which is often mentioned in the front street: that is to do a good cloth action! Generally speaking, there are two main conditions that lead to this type of pressed powder. The first is that there are more caked particles in the powder.

Caked coffee powder in cold weather and fine grinding will breed static electricity, which attracts coffee particles to each other and condenses into lumps. If they are not broken up before packing, these large particles will make it harder for the water to flow through during extraction, and then flow to other places, creating a channel effect.

So if there are too many pieces of coffee powder, we'd better use a cloth powder injection to break it up. If you don't have a friend with a cloth powder needle, you can also use multiple needles instead. In this way, a large number of caked coffee powder can be eliminated and the channel effect can be reduced.

Pressing powder this is the hardest hit area of the problem, many friends will think that after using the cloth powder dispenser, pressed powder is already very flat and does not need to be pressed or pressed any more. Therefore, the powder is often not pressed, or concentrated extraction is carried out after gently pressing.

But in fact, the pressed powder flattened by the powder distributor is only flat on the surface, and the internal structure is still loose and scattered. The extraction of espresso is pressurized, if there is not a tight pressed powder to resist the pressure, then the strong water impact will easily pierce the pressed powder out of the hole, resulting in a channel effect, pressed powder is therefore more likely to be broken.

Therefore, Qianjie suggests: if the pressed powder often breaks and contains dried coffee powder, you can try a cloth powder injection to disperse the powder, or increase the strength of pressing the powder. reduce the breeding of channel effect ~ (Qianjie has a saying: moderate strength, not too big! The following is an error demonstration)

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