The basic tool of hand-brewing coffee the extraction principle of triangular filter cup is better than the filter cup with several holes.

Pour over means to pour water and let the coffee particles tumble properly to release the coffee substance, that is, to make a cup of coffee. Hand brewing is one of the most widely used ways to brew coffee. It only needs simple utensils to start brewing coffee. And the way there are so-called hand drip (follicles) and pour over (brewing), although the way will be slightly different, but the brewing process still have to pour hot water into the filter cup, so let the hot water evenly attached to the coffee particles, is the only way to make a good cup of hand-brewed coffee. Before we talk about the principle of hand cooking, let's introduce the utensils that will be used and the main points of selection.

A small disadvantage of the French press mentioned earlier is that the fine powder is not filtered clean enough and often remains in the cup, resulting in a bad taste, and if the metal filter is not cleaned up, it will often leave a smell and affect the flavor of the coffee. In view of the hassle of cleaning, a lady named Ms.Melita used filter paper to filter on a whim. As a result, the way of hand brewing coffee is derived, and the filter cup is one of the most important tools of this coffee brewing method.

Filter cup

Filter cup is the most basic tool in hand-brewed coffee, which is generally divided into cones and triangles, while triangular filter cups are first widely used in hand-brewing types. In this article, the principle of hand-brewing is introduced, and the triangular filter cup will be used as the main explanation.

Hole number

At present, the filter cup brands that can be found on the market are Melita filter cup which has been widely used and Kalita filter cup from Japan. The biggest difference between the two is the difference in the number of holes at the bottom. In the early days, there was only one hole in the bottom of Melita, but its disadvantage was that when the coffee was worried too much, the hole was often blocked by fine powder, which made the coffee soaked in the water for too long and made the coffee bitter. Therefore, the brewing method of adding water was adopted for this kind of filter cup, in the hope that the coffee particles could always float on the surface, but the relative problem was that the coffee particles were soaked in the water for a long time. It will affect carbon dioxide emissions and reduce the extraction rate, so a three-hole Kalita filter cup will be derived later.

Rib frame

In addition to the number of holes, we can also find that there are protruding designs in the filter cup, which we call the ribs of the filter cup. The main purpose of designing these ribs is to prevent the filter paper from being affixed to the filter cup, so that the hot water poured into the filter cup will flow directly along the filter cup wall through the filter hole and run to the next pot, so that the hot water soaked coffee powder will not be able to extract the coffee liquid, which will eventually reduce the extraction rate. The taste will also become thin and light. The drip punch is supposed to replace the troublesome flannel, but the filter paper is a fragile material, so a filter cup is needed to prevent the powder layer from collapsing during water injection, and the filter paper itself will permeate. If it is completely attached to the filter cup, the water will flow directly through the filter hole on the cup wall and reduce the extraction efficiency, so there is a rib design on the filter cup, which can help the distance between the filter paper and the filter cup wall to prolong the time for coffee particles to be immersed in water. After being soaked in hot water, coffee particles will emit carbon dioxide, and many bubbles will be seen on the surface, while the internal particles will expand because of absorbing hot water. In addition to the path of discharge to the surface, there is also one of the exhaust paths around the filter paper, but if the filter paper is close to the edge of the filter cup, the heat cannot be discharged smoothly, so the coffee particles suffocated at the bottom will be affected. As a result, the injected water can not be absorbed by the coffee, and the amount of extraction is reduced.

However, the ribs of the filter cup are not deep, because its purpose is to let the hot air have room to discharge, so the filter cup with neat arrangement and uniform depth is the first choice.

Generally, there are filter cups made of ceramic and plastic on the market, and the choice still focuses on the quality of ribs. Ceramic is a very good choice in heat preservation, but because it is not easy to form clay, it often makes the ribs of different depths. So plastic filter cups are more economical and affordable. At present, there are more copper filter cups on the market, and the material insulation of copper is much better than that of ceramics, and it is also more stable than plastic in molding. The only disadvantage is that the price is too high, so if the budget allows, the copper filter cup will be the best choice.