「Hand pouring technique」The key factor affecting coffee brewing: water injection

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There are three Ts in hand pouring: Time, Temperature, and Turbulence. Today I’m going to introduce you to water flow, which is Turbulence among the three Ts.

When practicing hand brewing, we often practice water injection techniques, such as whether the water column is vertical enough, whether the water is cut off during the circle, whether the size of the water flow is consistent, etc. After all, what role does the shape of the water flow play in brewing?

The water flow during hand brewing is mainly to help the coffee be properly stirred and evenly extracted!

Therefore, we can control the size of the water column to:

1. Change the degree of powder stirring.

2. Extend or shorten the extraction time.

The two are in a relative relationship when the water flow is controlled. That is to say, when the water flow is large, the coffee powder is stirred to a greater extent and the extraction time is shortened; when the water flow is small, the powder is stirred to a lesser extent and the extraction time is extended.

But what is the appropriate water flow size?

First, we can think about whether the purpose of the current water injection is to ① change the degree of agitation of the powder, or ② extend or shorten the extraction time. Then, we can determine the water level in the filter cup at that time and which form of water flow is suitable.

For example:

High water flow: It can effectively stir the powder, but it will also cause the water level to rise rapidly, causing flooding, accelerating drainage, and easily reducing the extraction rate. (So when the water level in the filter cup is too high and the coffee powder has absorbed a lot of water and saturated and sunk, be careful when using high water flow).

Small water flow: Although it will not flood the coffee cup immediately, too gentle water injection will make the water column unable to penetrate the powder layer, and can only stir the surface, and the brewing time will be longer. (When the coffee powder absorbs water and sinks, it is easy to over-extract the surface of the powder layer and under-extract the lower layer, resulting in impurities).

A large water flow will promote stirring, but it will easily shorten the extraction time and lead to insufficient extraction; a small water flow will easily lead to unbalanced extraction due to uneven stirring. So, how can we avoid flooding while effectively stirring and extracting as evenly as possible?

There is an idiom that I believe everyone has heard: water drops wear away the stone.

This idiom is not meant to give you a bowl of chicken soup like telling you to keep practicing, but it is telling you a truth about water flow: as long as you persist in working hard in the same field, you will definitely achieve some results!

Ahem~ It’s really not chicken soup! In fact, it’s this: as long as you insist on injecting water at one point, you will definitely be able to penetrate the powder layer.

Just like the Japanese drip method, even a little bit can make a big hole. If you want to use a thin stream of water to evenly stir the powder layer, you have to use a "slow" circle. If the speed of the circle is slow enough, even a relatively small stream of water can penetrate the powder layer and stir the lower layer of powder. In this way, you don't have to worry about uneven extraction!

So what should I do with the big water flow? It's hard to control the small water flow of my big-mouthed kettle! If I just pour it in, won't it all flow out quickly?

Don’t worry, we have a way to control the extraction time without changing the equipment or the grinding coarseness: inject water in stages!

Wouldn't it be easy for a large water flow to cause the water level to be too high and drain too quickly? Then inject water in sections. Whenever the water level is higher than the top of the powder layer, and you intend to bypass the powder bed and slide into the surrounding gaps, you can cut off the water. In order to achieve uniform mixing during intermittent section injection, large water flow "section injection" is often combined with "fast" circling.

Finally, I would like to briefly summarize my views on water flow. You can also think about the size and shape of the water flow during brewing, the relationship between the water level, time, and degree of stirring during brewing, and when to match the relative water flow.

■The main purpose of controlling the water flow is to (1) change the degree of powder agitation; (2) control the extraction time.

■Large, fast currents are like thunderstorms, which can quickly stir up the powder layer but will also cause the water level to rise rapidly.

■A small stream of water may only disturb the surface powder and extend the overall brewing time.

■The amount of water flow to be used can be determined by judging the water level in the filter cup at that time.

■The "#drippingwaterwearsstone" technique is a good way to effectively use small streams of water to stir up the bottom powder layer.

■The "#segmented water injection" technique is a little trick to extend the extraction time under high water flow conditions.

Why do some people think that water injection is complicated? In addition to not understanding some of the above knowledge points, in fact, whether it is changing the degree of powder stirring or controlling the extraction time, the same purpose can be achieved by changing different filter cups and changing the grinding coarseness of coffee powder. In other words, if you want to analyze each person's water injection technique in detail, you must comprehensively consider the complex combination of the filter cup, grinding coarseness, and water flow. If you only know one thing but not the other or the third, it is undoubtedly imitating others.

Finally, if you have any questions about hand-brewed coffee, you can leave a message to the editor!

【Recommended reading】：

Four factors to consider when choosing a pour-over filter cup: material, flow rate, filter media, and cup size

Daily Brewing | Should I use a high or low water flow to brew coffee?

[Hand-brew water pouring practice skills] I always hear that practice more will improve the quality of life, but how do you actually practice hand-brewed coffee?

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