Analysis: what is the coffee powder press? how strong is the coffee powder press?

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When I first learned to make espresso (espresso), there was one step that gave me the biggest headache: pressing powder.

The function of pressing powder is to flatten the coffee powder evenly in order to create a high pressure to "squeeze" the coffee out. There are two requirements for this step: deep pressing and flat pressing. Some people say that it is necessary to use 30 pounds of hand power to press powder, so what is the concept of 30 pounds of hand power? To be honest, I don't know, and it's difficult to show it technically, so now some coffee instructors simply use the concept of "weight" to teach students to press powder. After all, weight is easier to understand than hand power. Every time you press powder, you move your center of gravity and use weight as pressure. In this way, you can maintain the consistent powder strength.

Using weight as the standard may solve the problem of powder strength, but to press pressed powder evenly depends entirely on the feel, and you only have one chance to try it. If the feel is not good, the uneven pressing powder can only redo the whole brewing step rather than repeat the pressing powder, it is said to avoid internal cracking caused by the double pressing powder and form a channel (channeling). If there is a slight deviation in the angle of the wrist or elbow, the pressed pressed powder will not be distributed evenly, which results in uneven extraction. This is also the part that annoys me. It took me nearly a few months to find the feel to press the coffee powder evenly.

Traditional type

Simple structure, handle plus chassis, can be split or one of the two. Materials can be made of all stainless steel or all wood, common is handle wood, chassis with stainless steel. The wood feels good and is favored by baristas. The way of holding this traditional powder press is the same as holding the doorknob, and the palm is the part with the most force. Therefore, the slightly fastidious merchants will design the end of the handle thicker, which is in line with the shape of the palm half grip. Although it is comfortable to hold, this way of gripping actually increases the pressure on the wrist and is easy to cause industrial injuries to the wrist. According to the survey, the wrist problem of baristas is the main cause of work-related injuries in cafes.

Macaron type

In view of the fact that the traditional grip can cause wrist strain, some people have begun to redesign the powder press in order to be more in line with artificial physiology. In 2015, Clockwork Espresso from the UK designed a powder press similar to the dessert macaron, with an easy-to-understand name: PUSH. It is divided into two parts: the upper part is wider than the coffee maker handle (portafilter), and the lower part can adjust the height to ensure that the powder press does not exceed the set height when pressing the powder. When pressing the powder, just "press" it, so that it can be consistent. Other similar brands include Mahlgut Buzzer from Germany. I have never used these two brands (too expensive). I have only used similar imitations. The first feeling: it not only solves the problem of powder strength and average, but also solves the problem of abnormal bending of wrist caused by traditional grip. However, in order to "press" the powder press with the palm of the palm, the barista's wrist inevitably bends and is not suitable for high-flow cafes in the long run.

Seal type

This has nothing to do with the shape design, more like the principle of operation. The shape design is traditional, but the mode of operation is very different. Install a spring between the handle and the chassis and press the powder like a seal, simple and fast. The powder strength depends on the spring material, such as Espro Calibrated Tamper and The Force Tamper. After reading the introduction of both, I prefer the design of The Force Tamper. Unfortunately, it still can not solve the problem of the bending extent of the wrist.