Unexpectedly, hand-brewed coffee will also have a channel effect!

The "channel effect" refers to the fact that water relies on inertia to find a shortcut and pass through it in the process of extraction. because this part of the water which takes a shortcut does not play a complete extraction role, it eventually leads to a phenomenon of uneven extraction. Qianjie often mentions the channel effect, mostly in the articles about espresso! But in fact, not only Italian, but also the extraction of hand-brewed coffee will have a channel effect!

The reason why the channel effect of hand extraction almost always refers to the channel effect is Italian coffee, because once this effect occurs, it will have a great impact on the taste and flavor of Italian coffee. The impact of hand-made coffee is relatively less, and because of the visualization of the extraction process, we can remedy it in time after some channel effects occur.

Generally speaking, filter cups, such as V60 and Origami, which use guide bones to support filter paper and create water flow gaps, are more likely to produce channel effects. Because this kind of filter cup is to avoid soaking for too long during cooking, there is a situation of extraction and specially create gaps, in order to let the water pass faster!

Therefore, when injecting water, the hot water is not all infiltrated down, but at the same time, it will flow out from the gap created by the surrounding diversion bone, and the launching speed will be greatly accelerated! Generally speaking, the surrounding area is covered with coffee particles because of the impact of water, so before hot water passes through these cracks, it will "take away" the soluble matter hidden in the coffee powder wall!

However, if the injected hot water is not washed on the coffee powder wall, then this part of hot water will seep directly from the gap, and the boundary will not play the role of extraction, but will directly drop the pot, which will have a certain impact on the extraction and taste of the coffee. This is what we call the channel effect. A relatively minor situation is that there is too much hot water injected into the powder bed! Due to the limited amount of coffee powder, the filter paper will not be completely covered, so when the hot water is submerged over the boundary of the powder wall, this part of the hot water will slip directly through the gap in the top and do not participate in any extraction!

But this is, as we say, a situation with less impact. Because only a small part of the hot water in the top layer is affected, other hot water in the powder bed can still play a good extraction role. if we use multi-stage cooking, then we only need to change the way of water injection during subsequent brewing. can avoid some negative feelings! Then there are some irreparable situations: when we finish cooking, if you find a large gap in some parts of the powder wall, you can see the filter paper visually, then it means that due to the improper cooking method (continuous large-scale circle, or fixed-point water injection in the corner), there is a channel effect on the way of extraction! Because it is the state observed at the end of the extraction, it is almost impossible to remedy!

But some of the above channels are relatively light, to say serious, is to be able to see very abrupt faults!

This is due to the excessive impact of the water column during water injection, which breaks down the powder wall. This kind of situation is more serious, a large number of unextracted hot water is directly filtered to the pot, the only function is to affect the final taste of coffee! Light, astringent miscellaneous is the most common performance of coffee with this kind of pink wall!

Of course, not all pink walls that are strongly impacted will have the performance of faults! For example, at the beginning, although the powder wall suffered a greater impact and produced a fault, because the subsequent brewing led to a rise in the water level, the coffee particles at the top would re-cover the broken powder wall when falling, creating the illusion that the extraction was normal! Therefore, when we observe the channel effect in the extraction process, be sure to modify the cooking method next time: reduce the water injection around the large circle to avoid flushing to the edge of the cup, lower the water injection height to reduce the impact of water flow, and so on. all these can effectively reduce the occurrence of channel effect.

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