Coffee hand flushing technique: central water injection

Many friends feel that the central water injection method may not be able to extract completely, but my feeling is that the central water injection can extract completely, but the immersion method will be lighter. I have been using the central water injection method since I touched the hand, that is, I only inject water in the center without spreading it, and a small hole will be formed after extraction. As opposed to the central water injection method is the immersion method, that is, the whole coffee noodle is injected with water. Many friends feel that the central water injection method may not be able to extract completely, but my feeling is that the central water injection method can extract completely, but the immersion method will be lighter, for the following reasons:

First of all, we have to make two points clear:

1. The coffee powder in the cup is actually honeycomb

Because of the honeycomb gap, water can pass through the coffee powder to extract the water-soluble substance from the coffee.

2. The taste of soaking depends on the soaking time.

The taste of coffee depends on the soaking process of coffee powder in water, that is, the coffee powder is fully soaked and the taste is strong, but if the soaking is not enough, the taste is relatively light, so the water storage capacity of the brewing tool is an important factor. Flannel has a stronger water storage capacity than filter paper, so the flavor of flannel is stronger than filter paper extraction.

3. the water injected from the middle flows through the most coffee powder, and it is also the most complete brewing.

From this picture, you can see the direction of the water injected in the middle:

Through the above three points, we can see that if the whole coffee noodle is injected with water, the upper end of the bowl, the part close to the cup wall, if injected there, the water will only pass through a small part of the coffee powder, and reach the cup wall, exudate filter paper, flow down the cup wall, and flow directly out of the cup, and this part of the water will be lighter, while the water injected in the center will be extracted more fully because it passes through more coffee powder honeycomb structure. So the taste is also strong.

These are some of my understandings. If any students have any objection, please do not hesitate to comment.

Source: John Private Coffee