What is the effect of the flow of hand-brewed coffee on brewing? How to determine the speed of water injection per hour?

Big current and small current are not only the resident guests in Qianjie articles, but also the words often mentioned by major baristas when discussing brewing! But many friends have some misunderstandings about the definition of the two, so Qianjie will share today what kind of water injection is a large flow and what kind of water injection is a small flow!

Misunderstanding of water flow many friends' misunderstanding of water flow lies in: "I think that a small flow is the injected water is relatively soft, and the stirring strength is weak; a large flow is a rough, powerful column of water!" But in fact, the size of the flow refers to the speed of the flow, how much water is injected per second during cooking. As mentioned above, the impact of water flow is mainly related to cooking techniques and water injection height, small water flow can also have a strong penetrating force to make coffee powder tumble, while large water flow can also be injected very gently.

The second is the difference in water flow caused by the spout, as we described in yesterday's article! The same amount of water, the same tilt angle, but different spout types will make a difference in the amount of water. The flow from the small spout is generally small, and the flow from the wide spout is generally too large. therefore, when we discuss the flow of water, there is often a certain difference in communication because of the difference in the spout.

At this time, a friend will ask, "how do you measure the speed of your current?" In fact, it is very simple. Now many electronic scales have the function of measuring speed, which can measure the "hour" speed of water flow while recording weight.

What about friends who don't buy this kind of electronic scale with speed measuring function? It doesn't matter, share a method to measure the flow rate of water injection under the front street!

How to measure the flow rate of water injection? First of all, we still need to prepare an electronic scale, a conventional one is fine, and there is no need to have a speed measurement function! Then, put an arbitrary container on the electronic scale, and then we inject water according to the usual way of water injection, and start timing.

Time ten seconds, then divide the amount of water injected in those ten seconds by 10, and you will get your speed of water injection per second! The front street uses a copper kettle transformed into an olecranon, with a minimum flow rate of 2.2ml/s and a maximum flow rate of 9ml in the case of a vertical water column, and then switch to a Kalita copper kettle with an elephant trunk, and the minimum flow velocity is 4ml/s and the maximum water velocity is 12ml/s in the case of vertical water column. In multi-stage brewing, most people do not use a single water to brew, because the coffee is not said to be bad, but not so good. Therefore, you can cook according to your own way, and then match it according to the effect of the flow.

What are the different effects of large and small currents? Just by using the size of the water to brew a pot of hand-brewed coffee, you can directly see their effect! The cooking parameters are as follows: the beans are used as Guatemala New Oriental Rose Summer, the grinding degree is 9.5 degrees of Ek43, the ratio of powder to water is 1:15 (beans 15g, 92 °C hot water 225ml), and the cooking method is three-stage.

First, the cooking time: the whole cooking time with small water flow is 2 minutes 05 seconds, and the cooking time with large water flow is 1 minute 57 seconds. It can be seen that when the cooking parameters are the same, the cooking time of small water flow is longer than that of high water flow. Second, the height of the powder bed: we often say that raising the powder bed means that when the amount of water is lower than the amount of water injected, the position of the powder bed will be raised. The greater the gap between the amount of water and the amount of water injected, the faster the powder bed will be raised. Therefore, combined with the first point, we can know that the speed of lifting the powder bed with a small flow will be slower, and the speed of the large current lifting the powder bed will be faster.

When we talk about raising the powder bed, we generally refer to the use of large water flow to open the gap between the amount of water and the amount of water injected, so that the powder bed can be raised in the shortest possible time. Third, flavor performance: due to the slow launching speed of the small water flow, the coffee flavor washed out by the small water flow is relatively rich and concentrated, mainly because the extraction time is longer and the stirring times are more; while the launching speed of the large water flow is faster, so the coffee flavor washed out by the small water flow will be more prominent and clear, but compared with the coffee washed by the small current, it will be relatively light and thin.

When to use a large current and when to use a small current? With regard to the choice of water flow during cooking, Qianjie suggests: "improvise". Because they are mainly selected according to the cooking method used, the current state of the powder bed and the cooking time. If you are accustomed to using large water when cooking, then when the following occurs in the cooking process, it is best to adjust to a small flow! The speed of launching is much faster than usual: the water level should have been in the middle of the filter cup at this time, but because the grinding is too rough, the launching speed is too fast and is about to hit the bottom! Then at this time, it is necessary to switch to a small flow to prolong the extraction time and avoid insufficient extraction.

If you are accustomed to using a small flow when cooking, then when the following occurs in the cooking process, it is best to adjust to a large flow! Extraction time is too long: although a long time of extraction can get more coffee substances, but it is easy to extract bitter substances! If clogging and grinding lead to slow launching during cooking, it is necessary to switch to a large flow to speed up the launching and reduce the occurrence of over-extraction. When it is necessary to raise the powder bed: the small flow will raise the powder bed more slowly due to the small amount of water injected and the small difference between the launching speed and the launching speed. Therefore, when we need to raise the powder bed, it is best to use large water flow to quickly raise the powder bed after steaming, so that the coffee powder can be fully and evenly extracted!

Of course, the increase / decrease of water flow in Qianjie is to adjust the original water flow. The fluctuation in the process of water injection had better not be too great, and only a small amount of addition or subtraction is needed. For example, the flow rate of water used in Qianjie is 5ml/s. If it is necessary to increase the flow of water, it can be raised to 6~7ml/s, and there is no need to raise to the limit of 8~9ml/s.

-END-

Front Street Cafe

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