Introduction to the method of how to judge in advance whether there will be stagnant water in hand-brewed coffee

If after the end of the water injection in the hand-brewed coffee, it is found that the water hole is blocked by coffee powder and stagnant water, the only remedy is to stop the flow and remove the filter cup in advance to avoid excessive extraction.

If signs of stagnant water are found before the end of water injection, there are many more ways to save it. For example, adjust the way of water injection, do not inject water around a large circle, avoid washing down the coffee powder on the edge and increase the degree of blockage; or raise the water level of the powder layer so that more coffee powder is attached to the edge of the filter cup, thereby reducing the thickness of the powder bed; or use a large current to stir up the clogged powder bed. When making coffee, there are three time points to predict whether there will be stagnant water. The performance of a point in time during steaming. The degree of expansion of a coffee burger depends on the freshness and roasting of the coffee beans. The fresher the coffee beans are, the more obvious the expansion exhaust of the coffee is. On the contrary, when the coffee beans are not fresh, there is almost no reaction when the coffee is steamed. And the deeper the roasting degree of coffee beans, the greater the degree of expansion, can easily bulge a "hamburger" shape, while the lighter roasting degree of coffee beans, its hardness is larger, the degree of expansion is relatively small, sometimes not obvious. If the degree of steaming expansion of coffee is obvious, the phenomenon of stagnant water will not occur. And the degree of steaming expansion is not obvious, it is more likely to block the tail end of the problem of stagnant water. Therefore, Qianjie suggests that in the next water injection, we should pay attention to the extent of the circle is not too large. And in the subsequent water injection, it is necessary to raise the water level of the silt layer properly.

The second time point is the foam performance during water injection after steaming. If the foam is darker (brownish yellow) and more abundant, then you don't have to worry about blocking the water.

However, if the color of the foam is relatively light (yellow and white), and relatively thin (the surface is attached to a thin layer of foam), there may even be voids. This phenomenon means that most of the coffee powder has sunk on the powder bed, which is easy to block the sewer hole. In this case, if the water injection in this section is not over, you can increase the flow to stir the powder bed and try to make a small circle to avoid flushing the coffee powder on the edge of the filter cup.

The third time period is the observation of the falling rate of the water level before the last stage of water injection. If the launching speed is relatively slow during this period, it is necessary to use a larger current to roll the powder bed during the last stage of water injection.

Of course, if the problem of blocking stagnant water can not be solved by these three means, the final solution can only be used-river closure. Of course, river closure can effectively avoid bitter, astringent and other bad flavor produced in the tail section, but it also brings the problems of high coffee concentration and lack of flavor. The problem of high concentration can be solved by adding 10-20ml water to bypass. As for the performance of flavor, we need to find the cause of blocking stagnant water to avoid the same situation next time.