How to grind coffee beans into coffee powder? how to make espresso? how to adjust the thickness of coffee powder?

For small partners in the coffee industry, the most "numbing" thing every day, the grinding adjustment of Italian coffee takes the first place. With the different state of coffee beans from day to day, the size of coffee particles, the amount of powder extracted, the time of extraction, and the flavor of coffee will be different at the same scale. this also leads to drinking several espresso before starting business to determine a suitable extraction parameter.

The daily state of coffee beans will certainly affect the degree of grinding, but there are other external factors that will affect the degree of grinding of coffee. If you don't check the details and run into the right parameters in a casual state, how many coffee beans will be wasted!

Cleaning of residual powder in grinder cutterhead & powder bin / outlet

I believe that friends will clean the coffee grinder every day, but that is to clean the surface, it is rare to think of taking the knife out to see if there is any residual powder caking. Although the grinding cutter head does not need to be removed and cleaned often, it can not be left alone. Whether it is an Italian bean grinder or a single bean grinder, it is necessary to take out the knife head and clean it carefully every week! But don't wash it with water.

Like Italian coffee beans generally use medium and deep roasting above roasting, this kind of roasted coffee bean surface with the continuous release of carbon dioxide, will show a state of oil. The grease on the surface will more or less attach to the tooth lines of the cutter head during each grinding, and the coffee powder will stick together to form cakes after a long time. When the snout is caked, it will make the coffee particles grind unevenly, which will eventually affect the effect of coffee extraction.

On the other hand, the residual powder of the powder outlet / powder cartridge will be longer with the exposure to the air, and the flavor will slip away. When the freshly ground coffee powder is mixed with these residual powders for extraction, the coffee will show a bitter, woody and other unpleasant taste. Therefore, when the bean grinder is not turned on for more than 15 minutes, you need to use a tool to empty the coffee powder out of the powder outlet / powder bin and then re-grind and pick up the powder.

Temperature of cutter head of bean grinder

When the grinder runs at high speed for a long time, the cutter head will gradually heat up, and the cutter head heat will affect the two parts. One is that when the cutter head is grinding coffee in a hot state, the particles will become thicker / prone to uneven grinding. According to some studies, it is pointed out that under the same scale of the same bean grinder, coffee beans are ground under the cutter head at room temperature, the particle size will be finer and more uniform. The knife head with high temperature will make the structure of coffee beans more tough, so the particle size of the ground particles will be thicker or even uneven.

One is that the heat of the knife plate will accelerate the volatilization of the flavor substances in the coffee particles, and the temperature will also increase during the whole extraction stage, thus reducing the viscosity of the coffee. Do not think that the difference of a few degrees does not matter, the overall performance of coffee will often make "amazing" changes and performance because of this small gap.

Humidity of the environment

The moisture in the air will have different effects on the preservation of coffee beans and the grinding of coffee. Whether it is climate change or closing at night with air conditioning / heating turned off, the humidity of the environment will be different. Therefore, for coffee beans that need to be kept in a cool and dry condition, the lid of the bean warehouse should be covered every day, and the coffee beans should be transferred to a dry container or sealed in the original package when closing at night.

When the coffee bean / grinder cutter is damp, the coffee is very easy to agglomerate in the case of very fine grinding. If these agglomerates are not effectively dispersed, they are equivalent to "clumping" extraction in the process of extraction, that is, the water constantly scours the outer particles to cause excessive extraction, while the inner particles are not effectively extracted. At the same time, caking will also affect the flow channel of the powder layer, resulting in uneven coffee extraction.

The loading capacity of coffee beans in the bean warehouse

This is the most easily ignored detail! Many friends will only go back to replenish the beans when the bean barn "bottoms out". Ta-ba! Too much / too little of the bean barn will change the thickness of the coffee grinding.

When the bean warehouse is full, the coffee will be oppressed during grinding, so the ground particles will be finer; on the contrary, if the amount of beans in the bean warehouse is too small, the coffee beans will have enough space to form a "bouncing" state during grinding. so the ground particles will become thicker / uneven. Qianjie recommends that the loading capacity of the Italian coffee bean warehouse should be kept at 2x3 as far as possible, and the minimum state should not be less than 1max 3.

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