How to adjust the Italian bean grinder how to calibrate the coffee grinder use the debugging diagram to illustrate the parameters of Italian coffee

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Why do cafes adjust bean grinders every day?

Coffee shops have to adjust the grinding degree of coffee every day, and some even adjust it every few hours. Isn't the extraction scheme fixed? The same machine, the same coffee beans, the same extraction scheme, there will be different coffee? In fact, these three things do not seem to change anything to the naked eye, but in fact, subtle changes are taking place every day. Just like the principle of boiling frogs in warm water, if a cafe has a fixed extraction plan, it may not notice any change for a day or two, but until the quantitative change occurs in one day, that is to say, one day it is found that its own coffee has become unpalatable, and the loss outweighs the gain. So how does Qianjie adjust the bean grinder?

The significance of adjusting bean grinder

In the eyes of the guests, coffee machines, bean grinders and other machines belong to fixed assets, but in the eyes of coffee practitioners, they are consumables. The brewing pipe of the coffee machine, the steam boiler and the cutter head of the bean grinder will wear out slowly as long as they are put into operation, which are all variables. So baristas take care of it every day and do a "major overhaul" every once in a while.

Coffee beans are more likely to change. Freshly roasted coffee contains very active carbon dioxide, and what we call the appreciation period is the exhaust period of coffee beans. at first, coffee beans emit too much carbon dioxide. and then the days will tend to smooth and slow emissions, and when there is no more gas emissions, it can be said that this coffee has lost its freshness. In other words, the flavor of coffee beans changes all the time, especially after one night, the change of flavor state is more obvious.

When the coffee bean enters the grinder, the blade in the grinder will crush the coffee bean into powder. The smaller the distance between the blade and the blade, the smaller the coffee beans will be ground into smaller particles. The finer the grinding particles are, the tighter they are, and the more difficult it is for the water to pass through, thus greatly prolonging the extraction time. On the contrary, if the distance between the blades increases, the ground particles will become rougher, the flow of water will be easier to pass through, and the extraction time will be faster. To take a simple example, like stones and fine sand, water flows much faster through stones than fine sand, because there is more space between the stones for the flow of water to pass quickly. Therefore, the correct grinding is very important, and the particle size directly affects the quality of the extraction.

How to judge the quality of powder

To observe the coffee powder, the high-quality coffee powder should be powdered and gravel. If the coffee powder is soft, like flour, it means the powder is fine. On the contrary, if the coffee powder feels tough and rough, it means the powder is too coarse.

Qianjie Coffee debugging Bean Mill course

Different bean grinders have different adjustment dials, so you should check the model of the coffee grinder and read the instructions carefully to determine the direction and strength of the dial. In general, if you keep in the habit of checking the settings of the bean grinder, you only need to make very small adjustments. As long as you move the turntable within 3 mm, you can change the thickness of the powder. Although 3 mm is a very small number, the grinding time of the same coffee beans will change by 3-5 seconds.

Specific operation steps

Determine the direction of adjustment you need (finer or thicker). Make sure there are enough coffee beans in the warehouse, and the valve between the warehouse and the sharpening knife is opened so that the coffee beans can fall smoothly into the grinding area.

Turn on the grinder for 10 seconds and discard the coffee powder (these are coffee powders that have not been adjusted).

Use the coffee powder to make a cup of coffee to ensure the accuracy of the steps of serving, flattening and pressing powder. Like Qianjie Coffee, the extraction standard of espresso is the ratio of powder to liquid at 1:2 and the extraction time is between 25 and 30 seconds. Then when we test, we have to change the degree of grinding to achieve the parameters we want to use.

Qianjie Coffee uses time to test the stability of espresso parameters during each extraction. For example, the extraction time is 28 seconds after grinding in the morning, but it changes to 22 seconds at noon. At this time, you need to adjust the bean grinder so that the time tends to 28 seconds. Of course, time is only a reference standard, and the most important thing is to be confirmed by tasting.

The debugging of the electronic bean grinder mainly aims at two variables, the amount of powder and the degree of grinding. These two variables are mutual, and if you change one of them, the other will also change.

The ordinary electronic bean grinder adjusts the grinding and pulverizing time of the bean mill according to the pre-set amount of powder (please note that the amount of powder is adjusted by the mill based on time rather than weight). If you are not satisfied with the quality of your coffee, the first thing you need to do is to determine whether there is a problem with the amount of powder or the degree of grinding.

In general, the distance between the correct weight, flattened and powdered pressed powder and the outlet should be 5-6 mm. If the height of pressed powder is not in this range, you should try to adjust the powder output of the bean mill (that is, grinding and pulverizing time). When adjusting the amount of powder, the range of each adjustment should be between 0.2 and 0.3 seconds, and after each adjustment, you need to re-test the quality of the coffee.

The most difficult part of adjusting the electronic bean grinder is that when you adjust the grinding parameters, the distance between the knives will change accordingly, and the change of this distance will directly affect the powder output of the bean grinder, that is, the grinding and pulverizing time. If you want to make the grinding degree finer, the distance between the sharpening knives will become closer, and there will be fewer coffee beans passing through the sharpening knife at the same time. On the contrary, the distance between sharpening knives becomes larger, and more coffee beans pass through sharpening knives at the same time.

Therefore, when adjusting the electronic bean grinder, we should first grasp the relationship between the amount of powder and the degree of grinding. Thinking that these two variables change with the change of one variable, we need to constantly adjust the test in order to achieve the best results.

Every small change in the bean grinder will have a great impact on the overall quality of the coffee. Therefore, as a barista, you should re-measure and adjust the bean grinder every day to ensure the perfect quality of the coffee.

To master the gouache ratio, you can use a constant amount of coffee powder (for example, 18 grams) in the exercise, try to match different total coffee weight, and then compare the differences in taste, purity and mellowness. You need to decide the final gouache ratio according to your personal preference.

Only through constant practice and exploration can you make an espresso that really suits you.

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