The coffee powder grinding degree of Italian coffee is adjusted correctly the grinding scale of Italian coffee beans

When brewing coffee, we all know that the thickness of the degree of grinding is very important. If the degree of grinding is not found correctly or unevenly, the coffee is easily underextracted or over-extracted. Compared with hand brewing, cold extraction and other methods, the grinding degree of espresso is much finer and needs more precise adjustment in order to grasp the taste of espresso.

How fine is the grind of espresso?

With regard to the thickness of hand-brewed coffee, Qianjie will borrow China's No. 20 standard sieve, which can be calibrated by how much coffee powder particles pass through fixed-size meshes. Espresso is a pressurized short-time extraction, which means that it will magnify all the performance, positive flavor and defects, so it is more demanding for grinding. Coffee powder is more delicate than fine salt, the naked eye can not observe the degree of thickness and uniformity, the use of sieve is even more unrealistic.

If the degree of grinding is slightly fine, the water will pass through the powder layer more slowly and it will be easy to over-extract. If the degree of grinding is a little rough, the water will easily pass through the powder layer, and it is easy to underextract, resulting in such a deviation, which may only be 0.1 of the grinding scale. So we usually observe the flow rate and taste of espresso in the brewing process to determine the appropriate range of thickness.

How to determine the appropriate range of grinding degree first?

When we get a bag of strange coffee beans, the first thing we need to do is to determine the degree of grinding if we want to make a good cup of coffee. If our grinding equipment has not been used, we do not know how to determine the appropriate scale range, we can first use a small amount of coffee beans to debug in different scale ranges. When the coffee powder is ground to the touch of flour, the coffee powder can be felt by hand. It is soft without roughness.

At this point, we can apply the common formula of Italian concentration for extraction. Qianjie recommends using a liquid separation ratio of 1:2, that is, 1 gram of coffee powder to extract 2 grams of right coffee liquid for between 20 and 30 seconds. For example, the front street uses a powder bowl with a capacity of 20 grams, that is, 20 grams of coffee powder and 40 grams of coffee liquid. If the time is less than 20 seconds, the flow rate is too fast; when the concentrate flow rate is more than 30 seconds, the flow rate is too slow.

The fast flow rate means that the water takes too little time to pass through the coffee powder, and the taste of coffee is often light or sour. It needs to be fine-tuned at this time. Research grinding calibration usually depends on daily experience. If the time difference from the target is less than 5 seconds, you can adjust it 0.2 grid each time. If the time difference is too large, you can be bold and adjust 0.5-1 grid. Even if the time is too long to be too short, you can also lock the grinding scale range and slowly reduce the range. Similarly, the slow flow rate means that the coffee powder is too fine, the water is difficult to pass through the powder layer, and the coffee is easy to taste bitter, so it needs to be thickened.

How to find the correct grinding scale?

The formula mentioned above in Qianjie is only for us to quickly find the suitable grinding range, it does not mean that the espresso extracted in this way tastes good. Finally, we still need to judge whether the extraction is qualified or not according to the characteristics and taste of coffee beans.

If the taste of espresso is obviously bitter, but the concentration is moderate, it may be due to excessive release of bitter substances for too long, and the grinding degree can be fine-tuned. If the oil on the top layer of the coffee liquid is light and thin, it may be due to too much extraction at the end, which can reduce the weight of the coffee liquid, that is, less extraction, it is recommended to increase the ratio of powder to 1.5 to 1.7. When espresso is rich in flavor but with a short finish, you can properly extract more coffee liquid and try to adjust the ratio to 1Ru 2.5.

Finally, the extraction formula is only a reference, if it is framed by it, it is difficult to adjust the flavor, and finally can only keep investigating the grinding degree, wasting coffee beans. The ratio of 1:2 is not entirely suitable for the golden ratio of this kind of coffee beans, sometimes it may be good to drink at 1.70 or 2.5 at times. Time is not necessarily limited to 25-30 seconds, sometimes 36 seconds, 24 seconds is the delicious state of this coffee bean. Qianjie is the daily product of the store, so the adjustment of parameters will be based on the accumulation of daily experience. If we have a low amount of cups at home, it is difficult to grasp. Qianjie suggests that we can record it and summarize the relationship between extraction parameters and flavor performance. This is more conducive to our rapid adjustment, but also save unnecessary waste.

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