Why do you weigh the powder after you have a quantitative bean grinder for espresso?

This is a question from a guest friend: "Why do you use a quantitative bean grinder, but not use it directly after grinding like some chain brands, but weigh it again after grinding it, and then put it into use?" doesn't this lose the meaning of the quantitative bean grinder? "

Before we answer this question, let's take a look at what a "quantitative bean grinder" is.

Quantitative bean grinder the so-called quantitative bean grinder refers to a bean grinder that can set the weight of the ground coffee powder or the grinding time at one time. It is roughly the same as what the guest friend explained, which can help us reduce the time of weighing powder. Note, however, that time is reduced, not steps!

We can adjust the grinding parameters according to the amount of powder used. For example, if the amount of powder used in Qianjie is 20g, then we can set the corresponding gram weight or time according to the function of the bean grinder. The bean grinder in Qianjie is a timing function, and it takes 4.5 seconds to grind 20g powder. Therefore, it sets the time is 4.5 seconds! Yes, it's really convenient! Now let's answer the question raised by the guest friend: "Why do you still weigh the powder?"

Why weigh the powder? Although it can be timed and quantified, in many cases, the grinding opportunity due to the influence of other factors, resulting in the amount of powder grinding deviation! If it is 0.1g such a small deviation naturally will not have much impact. But often, the error can often reach more than 1g with the expected gram weight, so we have to use electronic scales to measure the powder weight! There are three main factors that lead to the change of extraction weight.

First, the question of warehouse pressure has been taken out in front of the street and said separately that in the absence of an "anti-jumping device" (an umbrella device in the bean grinder), the beans in the warehouse will form different pressure due to different quantities. This pressure will give to the coffee beans that are about to be ground. The more beans, the greater the pressure, the more uniform the ground particles; on the other hand, the fewer beans, the less pressure, the more uneven the ground particles! The same is true for quantitative gram weight!

Qianjie conducted an experiment: when the warehouse was full, 20 grams of coffee powder could be ground in 4.5 seconds. In the case of 1x5, only 18.7g powder can be produced in 4.5 seconds, with a difference of 1.3g.

Second, the principle of gap accumulation between coffee beans to understand ~ because coffee beans are not equidistant spheres of the same size, but belong to irregular objects, the order is disorderly, which makes the gaps between beans different. This will slightly affect the regular grinding bean grinder! Because of the difference in the gap, there is bound to be a slight error in regular grinding (±0.3).

Third, the addition of residual powder in the case of no grinding for a long time, Qianjie Association recommends that you first grind out 1 ~ 2g powder, discard this part of the powder, and then grind the coffee powder for extraction!

Because the last handful of ground coffee powder is likely to remain in the channel of the bean grinder, this part of coffee powder will not only cause quantitative errors, but also because of the loss of most of the flavor, about the concentration parameters to be extracted! (faster flow rate, uneven extraction)

Fourth, after adjusting the grinding, the quantity will change! Originally, you can produce 20g powder in 4.5 seconds, but after you refine it, 4.5 seconds may only produce 18.8g powder! If it is thickened, it will be increased! And, at least 1: 2 handfuls of coffee powder can not be in a stable state.

So, I believe we all have a general understanding of the reason: the main reason for weighing is to ensure that the number of grams is accurate and does not affect the extraction; moreover, when the taste deviates, it will be more convenient to adjust! And the convenience that quantitative can bring us is that it saves most of the control time, and you don't have to stare at the schedule and press the pause button.

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