What is the appropriate degree of grinding for hand-brewed coffee? What is the difference between the brewing water temperature and grinding ratio parameters for deep-roasted coffee and lightly roasted coffee?

As we all know, a QR code is attached to the packaging of beans sold on Qianjie. By scanning the code, you can see the detailed background story and brewing parameters about the bean. Then there are often friends who will take them to Qianjie stores after buying beans and ask Qianjie to brew them, because they report that they clearly brew them according to the recommended parameters, but the brewed coffee is not that good, so they think it will be a problem with their own brewing techniques and want to learn how to brew them in preschool streets.

To be reasonable, just like Qian Jie shared in the tweet he posted with fake hands, although the impact of the water injection method will be there, it will not be great. We just need to ensure that the injected hot water can all come into contact with the coffee powder and then use the right parameters, and it will basically be difficult for you to make a cup of coffee that is not good to drink. Unless your parameters are not used correctly. Water temperature, amount of water, grinding, and time are the four main factors affecting coffee extraction. The reason why many friends cannot make good coffee is that they have not used the right grinding. Because among all the extraction parameters, the grinding value is the only one that is invisible, people often mistakenly think that they have used the right grinding. But in fact, the coffee used is either not thin enough or thick enough, which makes the brewed coffee not taste good.

Since the grinding degree of coffee powder is not visible, in many cases we can only use other tools to make a rough measurement, or make a rough judgment based on the impact of the grinding degree. In terms of tools, there is a No. 20 screen. The grinding parameters shared by Qian Jie in the article are measured through the screen. If we want to judge by the influence of the degree of grinding, then the "reference object" has the taste of time and coffee. Under normal circumstances, the finer the grinding degree of the coffee powder, the slower the water will be. Because the gap between the particles becomes smaller and the area where hot water can flow is reduced, the drainage rate will be slower and the extraction time will be longer compared with the previous year, and vice versa.

The taste of coffee is easier to judge! Qianjie mentioned earlier that the grinding degree of coffee powder will affect the extraction time. The length of the extraction time is equivalent to the contact time between hot water and coffee powder. The longer the extraction time, the more time the hot water and the powder will contact. The higher the extraction efficiency, that is, more substances will be dissolved, and vice versa; in addition, the thickness of the grinding degree also determines the water-contacting surface area of the coffee powder. The larger the surface area, the faster the flavor substances will dissolve, and the faster the opposite. Combined with the impact of time, we can know that when the powder is ground, the longer the coffee extraction time will be, the larger the water-contacting surface area will be, and the higher the extraction efficiency will be, and vice versa. As long as we know this, we can judge whether the grinding degree is suitable for the current coffee beans through the taste.

How to do it specifically? Very simple! When brewing an unfamiliar coffee bean, we can first choose a set of extraction parameters that you think are appropriate to brew it. When the brewed taste is too bitter or too sour, it may be due to insufficient extraction or excessive extraction. When this happens, the grinding degree is adjusted according to the specific situation, and then other parameters are fixed. If it is bitter or over-extracted, adjust it to coarse grind; if it is sour or under-extracted, adjust it to fine grind until the brewed coffee tastes to your satisfaction.

Judging the degree of grinding by time is also a feasible way, but this method is more used in making espresso. For hand-brewed coffee, in addition to the degree of grinding, water injection, filter cup, density of coffee beans, etc. will also affect the time. Therefore, Qianjie recommends that if you do not have a sieve, it is best to judge whether the degree of grinding of hand-brewed coffee is qualified. Then, needless to say that finding the most suitable ground for each coffee bean is not only very troublesome, but also unnecessary (yes, but not necessary for Qianjie). Although the number of beans in Qianjie Bean List is as high as dozens, there are actually only three levels of grinding used, namely deep baking, light baking, and anaerobic baking.

When brewing lightly baked beans with high density and difficult flavor substances such as Front Street Essay Huaquai, Panamanian Poquet Rose, and Kenya Tomato, the grinding used on Front Street will be slightly finer, fine granulated sugar, 75%~80% sieving rate of No. 20 sieve, then mix with a water temperature of 90~93°C and a powder-to-water ratio of 1:15, and the time is controlled within 2 minutes to 2 minutes and 30 seconds; If you brew beans with heavy anaerobic, loose texture, and fast drainage speed such as Qianjie Boundary Manor·Xizhao/Big Navel, 90+·Eleta Rose Summer, the grinding degree of Qianjie will be fine on the basis of shallow baking and grinding, and then the sieving rate of No. 20 sieve is about 80%, and other parameters are the same. The purpose is to extend the extraction time of coffee and allow coffee to be fully extracted;

When brewing deep-roasted coffee beans such as Qianjie Indonesia Golden Mantonin and Brazil Queen's Estate, the grinding degree used by Qianjie is 70% to 75% of the sieving rate of coarse sugar and No. 20 sieve. The purpose of roughening is to reduce the extraction efficiency of coffee and prevent bitter substances from being dissolved in large quantities. Then the water temperature will also be appropriately lowered to 86°C~89°C, and other parameters will be the same.

So if we brew a pot of ice by hand, then we will refine the grinding by 1 to 2 grids based on the corresponding hot grinding. The main purpose is to enhance the extraction efficiency and reduce the impact of reducing water volume.

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