The underlying logic of three-stage brewing and water injection of hand-brewed coffee! What do we need to pay attention to in sectional water injection? What is the effect of steaming?

Since Qianjie introduced the three-stage style like that in the previous article, please click "Why does Qianjie always use the three-stage style to make coffee?" "this article), it seems a bit excessive not to give a teaching article. After all, in the usual articles, Qianjie in the cooking experiment is a simple summary of water injection, it is difficult for friends to imagine what to pay attention to and how to do it according to the text. So, today, Qianjie will share with you a detailed three-stage cooking teaching.

Before we can learn how to do it, we need to understand the principle and logic of three-stage cooking. Only by recognizing the reasons for the segmentation of water injection can we make better use of the three-stage style and rush out the delicious coffee in the ideal condition!

The principle of three-stage brewing is mainly through the artificial injection of hot water to extract the soluble substances in the coffee! In this process, sour, sweet and bitter substances will be released in different amounts according to the dissolution rate, and the longer the extraction time, the more complete the substance will be extracted (although it does not need to be fully extracted). Before the formal extraction, people will use a small amount of hot water to discharge the carbon dioxide from the coffee powder, after all, the existence of carbon dioxide will hinder the hot water extraction of coffee substances. After discharge, the remaining hot water is used for formal extraction. But often, injecting all the hot water at once can easily make the coffee taste too concentrated; moreover, the fault tolerance rate is low, and it is easy to make the brewing irreparable. As a result, the water injection other than steaming is divided into two stages to get a richer sense of hierarchy.

Of course, if you just divide the water injection into two sections, there will certainly not be such an effect after the last second and the next! So this involves an inconspicuous small node-"water injection interval"! When it comes to three-stage cooking, Qianjie always inserts a sentence after the second stage of water injection: wait until the bottom of the water level is about to reach the bottom and then inject the next section of hot water. And the waiting time is the interval between water injection. Some people on the Internet say that three-stage water injection is a way to keep the temperature of the powder bed fluctuating. Indeed, during the 30 seconds of steaming, the waiting time for the drop of the second stage of hot water is a stage that lowers the temperature of the powder bed, and the temperature of the powder bed will not rise until the next stage of hot water is injected.

During these intervals, the temperature of the hot water in the kettle is also decreasing, and when the third stage of water injection is reached, the extraction efficiency has been reduced to a certain extent compared with the beginning. Therefore, under the condition that all the extraction parameters are normal, the extraction efficiency of the third stage hot water is no longer enough to extract all the remaining bitter substances, and the over-extraction situation is greatly reduced. Therefore, three-stage water injection is so popular because it highlights the flavor and does not allow over-extraction to occur frequently. So let's get back to the point and start our cooking teaching.

How to punch the three-stage style? According to the usual practice, first list the cooking parameters used in the front street: the amount of cooking powder: 15g grinding scale: the 10 scale of ek43 for shallow baked beans and 80% of the over-screening rate of screen 20 for shallow baked beans; and the 10.5 scale of ek43 for deep-baked beans, which is also 80% of that of sieve 20. (for the same reason for screening rate, please click "the same grinding scale, but different thickness?" Water temperature: 90 °C ~ 92 °C for shallow baked beans and 86 °C ~ 88 °C for deep baked beans. Powder / water ratio: 1:15 use filter cup: V60/Kono

The first stage of three-stage steaming: first of all, use twice the amount of water 30ml to steam for 30 seconds, circle from the center to the outside, quickly inject hot water and expand the range.

As we all know, "steaming" is to discharge the carbon dioxide from the coffee, so that the subsequent hot water can better extract the substances in the coffee. But it also means that this part of the hot water used for steaming can extract the least coffee. That's why people limit the amount of water used in steaming to twice that of powder, either because it's just enough to moisten the powder bed, and because it's just the amount of water that dry coffee powder needs to absorb (though not all of it). Note: since steaming has already started at the time of injection, we need to press the timing button to start timing and quickly inject at the same time (or before).

The second stage of the three-stage type: after the end of the main extraction to be steamed, we use 120ml hot water and use a small flow to inject in a large circle at a uniform speed. It is estimated that the injection will be completed in about 55 seconds.

After steaming, this extraction is a very important stage! The taste of a cup of coffee depends on the extraction of this section, and the water temperature at this time is still in a relatively high state. After "taking off" the carbon dioxide protective shell, the coffee powder bed is brewed with hot water, which can easily release the sweet and sour substances.

The third stage of the three-stage style: when the water level is about to bottom (coffee powder begins to show), we inject the last section of hot water (75ml) and inject it in a small circle around the center of the filter cup.

This section of hot water is the last part of three-stage cooking! As the article in Qianjie yesterday said, it belongs to a stage that can correct the deficiency. If the second stage of hot water does not decrease infiltration at a normal flow rate, we need to determine the use of water flow according to its speed! When the water level in the second stage falls too fast, it is easy to cause insufficient extraction, then we need to use a small flow to prolong the extraction time and increase the extraction rate of coffee; if the water level falls too fast, it is easy to block the extraction. Then we need to use large water flow to raise the powder bed, increase the permeable area of water flow, and speed up the flow rate.

Finally: different coffee substances are extracted from each section of hot water, and they will have certain barriers because of their different concentrations and will not be fused together. If we drink it directly at this time, it may not be too comfortable. So we need to shake this pot of coffee, "corrugated", and merge them all.

At this point, we can enter the real drinking link ~ clean and full coffee flavor, the rich and changeable level is the "supreme" enjoyment that three-stage brewing can bring to us.

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Front Street Cafe

No. 10 Baoqian street, Yandun road, Dongshankou, Yuexiu district, Guangzhou, Guangdong province