How big is the difference between powder bowls and powder bowls? How much powder should the coffee powder bowl contain? Which is better, a 51mm or a 58mm powder bowl?

The "powder bowl" is a bowl-shaped object installed on the handle of the coffee machine, which is called the powder bowl because it is loaded with coffee powder. Since the manufacturer will directly equip the default powder bowl when buying a coffee maker, most friends will not study the powder bowl (it is really not necessary). Most of the understanding of the powder bowl is that it is just like filter paper. it only acts as a filter.

Yes, but in fact, its function is not limited to that. If you have recently looked into the problem of espresso extraction, you should have seen this sentence: "concentrated extraction is not good, the chances are that the powder bowl has not been chosen correctly." The implication of this sentence is that the powder bowl will also affect the extraction of espresso. So the question is, is there any difference between a pink bowl and a pink bowl? How does the powder bowl affect the extraction?

I have no idea? It doesn't matter ~ in front of the street today, let's briefly introduce in what ways the powder bowl affects the extraction of espresso!

If you open any search software to search for the diameter of the powder bowl, there is a good chance that we will be able to see the numbers "51" and "58", which mainly refer to the popular diameter of the powder bowl / handle. When we choose a coffee maker, in addition to the function of the coffee machine, this value also needs to be taken into account when we purchase.

Because different coffee machines have different sizes of powder bowls / handles that can not be changed, each coffee machine and its accessories need to be uniformly fixed. When we buy related accessories, we have to buy the same caliber, such as powder hammer, powder distributor, secondary water distribution network and so on. Otherwise, it will not be used because the caliber does not match. It is worth mentioning that 51mm and 58mm are only two widely used diameters, in addition to other diameters. Generally speaking, the powder bowl / handle with smaller diameter is mainly used for household coffee machine or the old coffee machine, while the powder bowl / handle with larger diameter is mainly used for commercial / medium-to-high-end coffee machine.

The diameter of the powder bowl will have two effects, one is the surface area of pressed powder. When the diameter of the powder bowl is larger, the surface area of pressed powder is larger, and vice versa; the second is the thickness of pressed powder. Under the same load, the thickness of pressed powder in the large diameter powder bowl is smaller than that of the small diameter powder bowl. These two factors will affect the extraction of espresso. The surface area of pressed powder determines the surface area of water contact, while the thickness of pressed powder determines the resistance of pressed powder.

The capacity of the powder bowl is well known, and the powder carrying capacity of the powder bowl is limited. Because we need to ensure that the filled pressed powder can keep a certain distance from the water diversion network, too close or too far will affect the extraction of espresso. Therefore, the amount of powder used in each powder bowl is limited to a certain range.

For example, the capacity of the double powder bowl currently used in Qianjie is in the range of 18g to 21g, while the capacity of a single bowl is in the range of 911g. Here is just an example, there are many other areas, Qianjie will not be listed one by one. However, because the diameter of the powder bowl is fixed, the capacity of the powder bowl will affect the height of the powder bowl. Under the same caliber powder bowl, the greater the load of the powder bowl, the higher the height of the powder bowl, and the less the load of the powder bowl, the lower the height of the powder bowl.

In other words, the more the powder bowl is loaded, the thicker the pressed powder is. The thickness of pressed powder affects the resistance of pressed powder. When the pressed powder is thicker, the coffee machine needs to exert more pressure to extract. It sounds winding, but the simple explanation is that under a powder bowl of the same caliber, the more the bowl load, the thicker the pressed powder, the higher the resistance (the same grinding), and the greater the pressure required for extraction. This is the extraction effect of the difference in the load of the powder bowl (you can control it by adjusting the grinding degree of the coffee powder. Next time, open a separate article).

It is worth mentioning that when the amount of powder is small to a certain extent, the structure of the powder bowl will be changed. For example, the single fan bowl, which often appears as a "negative textbook", is insufficient thickness of pressed powder due to too little load, so it is necessary to change the shape of the powder bowl to increase the thickness of pressed powder. But at the same time, this makes the channel effect occur frequently, so it makes the single powder bowl become the product of being eliminated by the times.

The pore diameter and quantity of the powder bowl in addition to the shape of the powder bowl will affect the extraction, the pore diameter and number of the filter pores of the powder bowl will affect the extraction. When it comes to this, we have to mention the epoch-making "VST" for the powder bowl world. Before VST appeared more than a decade ago, the powder bowls of Italian coffee machines had a common design flaw, that is, the filter pores of the powder bowls were of different sizes. The big ones are very big and the small ones are very small. Then, this leads to an embarrassing phenomenon: too large filter pores will let a lot of fine powder through, increasing the bitterness of coffee, while too small filter pores are easy to be blocked by fine powder, unable to produce liquid. Therefore, the extraction condition of espresso was not optimistic at that time. Then VST founder Vince Fedele discovered the problem by accident, so he began to develop high-precision powder bowls: the pore size is not only more uniform, but also arranged in order, thus stabilizing the extraction of espresso.

Well, from the above episode, we can see that the pore diameter of the powder bowl has a great influence on the extraction. Its size and quantity mainly determine the flow rate of coffee liquid. Here in Qianjie, for example, under the condition that the powder bowl contains the same amount of powder and the same grinding, the larger the pore size and the more the number of the powder bowl, the faster the flow rate of the coffee liquid and the less the pressure on the extraction; on the contrary, the smaller the pore diameter and the less the quantity of the powder bowl, the slower the flow rate of the coffee liquid and the greater the pressure needed. There are two extremes, fast flow rate and slow flow rate, each of which is given a professional name in the industry: "high speed powder bowl" and "low speed powder bowl". The flow rate and extraction pressure can be adjusted by controlling the size and number of filters (so there are pressurized powder bowls with few holes).

The above is the main difference between powder bowls. But it is important to know that the opening sentence: "concentration and extraction is not good, chances are that the powder bowl is not chosen right" is not entirely true. One blogger said very well: "whether the food is good or not has little to do with the pot that conducts the heat, because the pot is mainly responsible for conducting heat, and it depends on the cook." Of course, different powder bowls have different characteristics, but the difference will not be too big, and the extraction logic is the same. As long as we understand the underlying logic of extraction, no matter what kind of powder bowl it is, we can extract delicious espresso (except for the old powder bowl, of course)!

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