What is the principle of making coffee by hand? How to control the degree of grinding and water temperature?

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What is the extraction principle of hand-brewed coffee? How to control the degree of grinding and water temperature?

Talk about the actual operation of hand-brewed coffee, but after consideration, decided to talk about the basic principles of hand-brewed coffee first, leaving the actual operation to the next article. My idea is like this: grinding, water temperature, time, ratio, these elements are related to each other, change one, will have a related impact on others, this involvement is particularly obvious in the conditioning of hand-made coffee. For example, fine grinding will slow down the speed at which water passes through coffee powder, coffee powder with poor freshness will reduce the time for water to pass through, and so on. Therefore, if you can have a deeper understanding of the basic principles, it will be easier to use in practice.

"the most important key to making coffee by hand is not the brewing technique, but the grinding and the control of the water temperature. "

A long time ago, I thought about an interesting question: if you want to rate a near-perfect cup of hand-brewed coffee at 100, then the scores for all aspects of the conditioning process, such as grinding, water temperature, brewing techniques, and so on, should be allocated in a reasonable proportion. Unfortunately, this kind of question usually can only resort to feeling, and it is difficult to give a scientific and quantifiable answer. The answer after my own reflection is that grinding and water temperature add up to about 80 points, and the remaining 20 points can be allocated to brewing techniques. When I put forward this idea in the May 4th Coffee Club, it was accepted by the members (or embarrassed to refute it), because every member has experienced that as long as we master the thickness and evenness of the grinding and make sure that the water temperature in the hand pot is appropriate, even if the brewing technique is not very skilled, you can still make a cup of delicious coffee (perhaps not perfect). This proves that brewing techniques are not the most important key to hand-brewing coffee.

The argument of reducing the importance of brewing techniques is bound to cause controversy and even infuriate a large number of coffee workers, because it seems to be a negation of their profession, but this is not my intention. After all, you need to have a good understanding of coffee before you can properly handle the details of grinding and water temperature. I would like to emphasize that to complete a successful cup of hand-brewed coffee, you should first score the relatively easy 80 points, and then use beautiful tricks to push the brewing to perfection in the remaining 20 points.

So next, we should study carefully, account for 80 points of hand coffee, grinding and water temperature, what are the details that should be paid attention to.