Hand-brewed coffee and water injection skills! How do I fill the coffee with water? The influence of the size of the brewing water on coffee! How to make coffee by hand?

Even if you use the same beans and the same parameters (grinding, proportion, water temperature), the coffee brewed by yourself is not as good as that drunk in the store. Qianjie believes that this is a question that many homeschooled friends will feel confused, but the answer is actually very simple, that is, the water injection is not good. In other words, it ignores the importance of water injection.

The difference between hand-brewed coffee and other extraction methods is that it requires human participation and continuous water injection throughout the process. The main purpose of this is to form a spoiler to accelerate the dissolution of flavor substances, while allowing coffee powder in different positions to receive almost the same extraction rate. And it is precisely because of artificial control, so some slight changes will affect the extraction rate. Qianjie often mentions that there are 30% soluble substances in coffee beans, but this 30% soluble matter does not require us to dissolve all of them, because not all of them are pleasing. According to gold cup extraction theory, coffee will have a popular extraction rate: 18% to 22%.

In other words, if we want to make a good cup of coffee, then we need to control the extraction rate within this range. In order to achieve this goal, in addition to the highly fault-tolerant parameters, it is also very important to be familiar with the principle behind water injection. This is why different people brew coffee with the same beans, the same utensils and the same parameters, but the taste of coffee is different. Therefore, Qianjie will share the underlying logic of water injection today. As long as we understand why we want to inject water in this way, we will know how to adjust the extraction rate, in other words, how to inject water!

First of all, let's talk about the logic behind segmented water injection. for most cooking methods, the most obvious difference is the number of segments of water injection between different ways. For example, one-cut flow is to inject the remaining target total water in one breath after steaming, three-knife flow is to divide the remaining total water after steaming into two stages, and four or six punches are divided into five sections.

Under the same ratio of powder to water, the more segments, the amount of water injected into each section will be reduced accordingly, and the extraction rate will be improved. There are two main reasons for improving the extraction rate, one of which is that the extraction time will be prolonged by stages. Because dividing the hot water into sections increases the waiting time for the hot water to permeate completely, which allows more contact between the water and the coffee powder, so the extraction rate is relatively higher.

Then there is the second and most important point. The reason why the water can dissolve the flavor substances in the coffee is that the hot water seeps into the coffee powder through capillarity, and then the flavor substances in the coffee powder move along the liquid from the inside to the outside of the powder because of the difference in concentration. The more the substance dissolves, the higher the concentration of the liquid outside the coffee powder. When the concentration difference between inside and outside the coffee powder gradually narrowed, the extraction rate also decreased. The purpose of segmenting is to reduce the liquid concentration outside the coffee powder, by allowing the liquid that has already become a high concentration to permeate and then inject brand-new hot water, so that a suitable concentration difference can be maintained inside and outside the coffee powder for a long time, so that the hot water has sufficient extraction efficiency. Therefore, combined with the above two points, the more the number of segments, the higher the extraction rate.

The water injection height determines the penetration force of the flow. When the position of the injection flow is lower, the penetration force of the water flow is relatively lower, and vice versa, the higher the position of the injection flow is, the higher the penetration force of the water flow is.

The penetration of water determines the extraction efficiency of coffee powder. The higher the penetration, the faster the dissolution rate of flavor substances in coffee powder, and vice versa. Like the example often mentioned in Qianjie, "the dissolution of granules": when we brew a packet of Radix Isatidis or other granules in our daily life, if we just rely on hot water to dissolve, then it will take a long time to achieve complete dissolution (the principle is actually the same as the previous one). Therefore, we need to stir with spoons or chopsticks to speed up the dissolution of particles. The same is true for coffee, except that the mixture is not spoons and other items, but a column of water.

What needs to be known is that when the water injection height is high to a certain extent, the water column will be changed into water droplets dripping, losing penetration. Therefore, when injecting water, the height is not unlimited. And, the higher the water injection height, the more the temperature of the hot water will be lost, thus reducing the extraction rate. For more details, you can go to this article and refer to → 's "effect of Water injection height".

Circle or fixed-point circle and fixed-point water injection is a point that is often discussed in the front street. Circle water injection is in the process of water injection, we will control the kettle to circle constantly, so that the location of the water column is constantly changing. The fixed-point water injection is to fix the spout above the central point of the filter cup and inject hot water continuously and motionless. (water injection in circles)

There is no difference between good and bad, and whether we use it or not depends on what we need to achieve at present. The purpose of circular water injection is to make the water column create eddies in the filter cup, allowing the coffee powder to follow the trajectory of the current. Although this can also increase the extraction rate, but relatively speaking, so that coffee powder can be evenly extracted is the most important purpose. The coffee powder located at the bottom of the filter cup will mainly be exposed to a high concentration of coffee liquid, so they will release less flavor substances than the upper coffee powder. In other words, it is still in a state of insufficient extraction. So by circling, we can take the coffee powder covered on the surface to the filter cup to build a powder wall, so that the hot water can be in better contact with the bottom coffee powder, and then get more abundant extraction. (fixed-point water injection)

Water injection at a fixed point because the flow of water is fixed at a fixed point, so the coffee powder it will affect is mainly in the range of the fixed point, and the extraction efficiency is relatively low. When the surrounding coffee powder has been fully extracted, or when the coffee has achieved a sufficient extraction rate, we will reduce the extraction rate by fixed-point injection of water, while allowing the coffee liquid to dilute the concentration to a good inlet range.

The size of the flow, then the last step is the size of the current, which indicates how much water we inject. The greater the current, the higher the rate at which we inject it, and vice versa. The large flow has a higher penetration force than the small flow (at the same water injection height), and because the rate is faster, the less time it takes to inject to the target flow. Without the intervention of fine powder (blockage), the extraction time with large flow will be shorter than that with small flow, and vice versa.

Similarly, there is no difference between good and bad! Large flow water injection can raise the powder bed by widening the gap between the speed of launching and coffee powder (as long as coffee powder can be driven), so the extraction is more uniform; small flow water injection ensures that hot water can stably contact coffee powder, and appropriately lengthen the extraction time, so that the extraction rate is higher. If you start to talk about it, it will greatly increase the length, so friends who want to know more about the influence of water flow can move to this article, →, "the influence of large and small water flow on cooking."

Finally, the last thing we need to know is that these factors are very important for water injection and are interlinked. If we only focus on the extraction parameters and ignore the effects of water injection, it will be very difficult to make good coffee. But when we are familiar with this principle, we can not only make a cup of delicious coffee more easily, but also adjust the way of brewing according to the state of the powder bed in time when facing some unfamiliar coffee beans. Making a cup of coffee is not too easy!

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