Principle of hand-punching extraction of coffee bean grinding

For example, the thickness of the powder, you can refer to the scale of the bean grinder, the particle size is also more intuitive visually, experienced friends even if changed to the bean mill also have a direct concept of the powder thickness. The amount of powder can be controlled by weighing, the level of water temperature can be controlled by temperature, extraction time and the ratio of water to powder, these are easy to control to be more accurate, so these factors are stable through continuous attempts and records.

There are two parts that are difficult to control and try to control. It is difficult to make two identical cups of coffee, which is also caused by these two factors.

One is the quality of grinding, which depends on the performance of the bean grinder. Today's technology still cannot grind coffee beans into a completely consistent coffee powder, and the difference in particle size will affect the stability of the extraction process.

The second is the convection of water, which goes back to the example of perfect extraction of two drops of water: a cup of coffee needs to extract not a coffee powder, but a pile, even if the particles are exactly the same size. we can't exchange each with two drops of water, which leads to the next factor.

The strength of convection

When we apply convection to hand flushing, there are many schools on the market: segmented water injection, one-time water injection, fast flushing, slow flushing, turning from the inside to the outside, flushing only in the center, there is also a very slow extraction of a little coffee and then diluted, and so on. The coffee produced by each genre has its own style, and the producers are often confident or even convinced of their own genre, but you may find that no matter which genre, you can make several kinds of coffee, some of which are not good at all.

To put it bluntly, the punching methods of these different schools mainly adjust the strength of convection, such as the strong convection of fast rush and the fierce exchange of water and coffee powder, which makes it easier to highlight the flavor and over-extract. The slow rush will be softer but the taste will be weaker.