Do I need to wait for the water to dry before pouring water? Hand-brewed coffee is the correct brewing technique!

Many novice friends often face a question when using multi-stage water injection to brew coffee, that is,"When should hot water be injected?"

The so-called multi-stage water injection refers to those methods that require dividing the hot water used in the coffee brewing process into multiple injections. For example, the three-stage water injection often used in Qianjie is a typical multi-stage water injection. When using multi-stage brewing, the timing of water injection in the third and subsequent stages is the problem: should we inject it before the previous stage of hot water runs out, or should we inject it after the previous stage of hot water runs out?

The timing of water injection shared by different bloggers is different, and the content shared on Qianjie is even used interchangeably. So this confused many friends and didn't know when to start injecting the next hot water. But in fact, things are not as complicated as everyone thinks. If the number of segments is not many, the impact will not be great. To know when hot water is injected, we only need to understand what impact hot water injection will have on extraction at different times. So this time, Qianjie will share with you based on actual operations what impact the different timing of water injection will have on coffee, and then how to choose the timing of hot water injection.

Brewing Experiment This time, Qianjie will use three-stage brewing to brew two sets of coffee, with two pots each. The grinding, water temperature, powder-to-water ratio, and water injection method of each pot of coffee are exactly the same. The only difference is the timing of injecting the third section of hot water. One group is when the hot water injected in the previous paragraph is about to flow to the bottom, and the other group is when the hot water injected in the previous paragraph is completely exhausted to see what impact different water injection opportunities have on coffee. (On the left side is the reference that the hot water in the filter cup penetrates until it is about to bottom out)

In order to minimize the impact of human brewing, Qianjie will use the accessory for hand-brewed coffee-a shower drip filter, which can divert the hot water we inject in this brewing experiment. In this way, there will be no obvious differences in extraction due to differences in water flow size and stirring strength (although this will happen, but it will not be so large in comparison).

Since this experiment did not judge the taste of coffee, Qianjie randomly grabbed a bean for the experiment. The extraction parameters were as follows: powder amount used: 15g Grinding degree: 10-scale powder to water ratio of Ek43: 1:15 Brewing water temperature: 92°C Use filter cup: V60 Water injection method: The three-stage brewing process is roughly the same for the four pots. They all use 30ml of hot water to steam for 30 seconds first. When the steaming process is over, it takes 20 seconds to inject 120ml of hot water into the second section. At this time, the time will come. 50 seconds. Subsequently, 75ml of the third section of hot water will be injected at different nodes according to their respective purposes. The injection of the third section of hot water will be controlled to be completed in 15 seconds.

Due to the proper control of the water injection rate, the flow rates of the four pots of coffee can be said to be the same. Almost all of the hot water injected into the second section of the four pots of coffee will run out in 1 minute and 10 seconds. Qianjie selected two pots to inject the third section of hot water at this time. The other two pots inject a third section of hot water after the hot water in the filter cup runs out (the time for running is 1 minute and 20 seconds), and then wait for the coffee to finish dripping, and start measuring the extraction rate.

The total extraction time of the two pots of coffee injected into the third stage of hot water earlier was 1 minute and 50 seconds. Through measurement and calculation, their extraction rates at 33°C were: 16.33% and 16.88% respectively; while the total extraction time of the last two pots of coffee injected into the third stage after the second stage of hot water was finished was 2 minutes, and their extraction rates at 33°C were: 17.30% and 17.58% respectively. It can be seen that even if the extraction parameters and water injection methods are roughly the same, the extraction rates still vary due to different water injection timings. There are two reasons for this difference, one is time, and the other is liquid concentration.

In the article "Why is it best to inject water into hand-brewed coffee in multiple stages", Qianjie shared that injecting water into multiple stages can effectively improve the extraction rate. The same reason is that water and coffee powder have more contact time. At the same time, the liquid concentration of extracted coffee will be relatively lower. Therefore, everyone should know how to decide the timing of water injection! When you want to get more extraction efficiency for coffee, you can choose to inject the next hot water after the previous hot water runs out. For example, when the grinding is too rough and the water temperature is too low, the flow rate of hot water in the previous section is too fast and insufficient extraction is prone to occur, we can wait for the hot water to finish before injecting it into the next section. Or divide the water injection into more paragraphs to further improve the extraction rate of coffee.

If you want to appropriately inhibit the increase in the extraction rate of coffee, for example, when the water temperature is too high, the grinding is too fine, and the flow rate of hot water in the previous period is slow due to blockage, you can move the timing of water injection forward slightly when these situations occur that may easily lead to over-extraction. The next section of hot water can be injected when the hot water injected in the previous section is one-third of the amount in the cup (or is about to reach the bottom). It should be noted that many friends think that the extension of waiting time will cause the temperature of hot water and powder beds to decrease, but will instead decrease the extraction rate. But in fact, the impact caused by temperature is not that great, and it does not affect time and concentration, so we don't need to worry about the impact of temperature drop due to prolonged time ~

- END -