Why can't an 18-gram powder bowl hold 18 grams of coffee powder? How good is the grind of espresso? How to determine whether the thickness of coffee beans is appropriate?

Many friends took advantage of the shopping carnival to buy a home coffee maker, but when the coffee machine was installed at home, they found that the operation of the coffee machine did not seem to be as simple as expected. Either there is no water here, or it cannot be installed there. As a result, some friends who live near the Qianjie store come directly to the door and ask some questions related to the coffee machine.

Then a friend's question impressed Qianjie very much. After he filled the coffee powder into the powder bowl, it was always difficult to buckle it into the head, sometimes even unable to do so. Even if the powder quantity is adjusted, it is difficult to change. At first, Qianjie thought that the problem might be on the rubber ring of the coffee machine, which was newer, more compact and less stuck. But after the friend took out a picture, the front street suddenly opened up, and the reason for the problem was that the powder was too full.

"because of the excessive amount of powder used, the coffee powder withstood the cooking head, which led to the situation that the card could not be put on. Generally speaking, after the coffee powder is filled and pressed into pressed powder in the powder bowl, there will still be some space in the powder bowl. Because the brewing heads of most coffee machines are designed to protrude outward, when we put the handle card on the cooking head, part of the cooking head will reach into the powder bowl. Therefore, the powder bowl needs to limit the amount of powder used in order to reserve space. When we use it, it is best to use the recommended amount of powder marked on the powder bowl. "

After chattering on the street for so long, the friend said, "however, I am using the recommended amount of powder in the pink bowl." 20g powder bowl, 20g coffee powder. Sometimes it doesn't even fit.

Then the problem is even simpler! It is because the grinding is too rough, so your 20g powder bowl can not hold 20g coffee powder! (there is absolutely no embarrassment on the front street) although grinding will not change the volume and size of the object, it will change the shape and size of the surface. When the coffee beans are ground finer, the coffee powder particles are smaller, and then the gap between the powder and the powder is smaller, we can control it to a thinner thickness by pressing; and when the grinding is thicker, the larger the grinding particles are, the larger the gap between the powder and the powder is. So naturally, due to the existence of a large number of gaps, coffee powder can not be pressed to a very tight density, 20g powder bowl can not hold 20g coffee powder. (exaggerated ↓)

In addition to grinding, the degree of baking will also affect the thickness of coffee powder in the powder bowl. With the same grinding and the same amount of powder, the deeper the roasting of the coffee beans, the larger the volume, and vice versa. This is because the degree of roasting of coffee beans determines the expansion rate of coffee beans, and the deeper the coffee beans are roasted, the higher the expansion rate and therefore the larger the volume. In addition, it also involves the problems of density and brittleness (which is too much to talk about, so I won't repeat it here). All in all, the volume of light-baked coffee powder is slightly smaller than that of deep-baked coffee powder at the same weight.

So, what's the solution? The solution is not to think about it, but to fine tune the grinding. When the grinding is so thick that the recommended amount of powder can not fit into the powder bowl, it shows that it is very close to the hand grinding thickness, so we need to adjust a lot of grids to the fine direction. And here are two places that can provide us with a reference to whether grinding is appropriate or not, the first is the dividing line of the powder bowl. As said above the front street, above the dividing line is the space needed for the head to be boiled, so we need to grind it so that the recommended amount of powder will not exceed the top of this line after filling.

Of course, not all powder bowls have a dividing line, so then there is a second reference object: extraction time. After all, after the filling pressure is completed, we will directly switch on the coffee machine for extraction, and then we can observe the extraction time to see if the grinding meets the goal we have set. For example, the target of this extraction is 20g powder, the weight of 40ml liquid is extracted, and the time is 25 to 35 seconds. If the flow rate is too fast and the time does not reach this range, it means that the grinding is still relatively rough and still needs to be adjusted finely. If the time is slow or just right, you can determine whether the taste is appropriate by tasting, and then make minor adjustments according to the taste.

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