What is the method of "three warm hands"? Introduction to the principle and parameter characteristics of variable temperature cooking

In the world of coffee brewing, in addition to the beans themselves, there are three main variables that affect the extraction stage, namely, grinding degree, water temperature, and the ratio of powder to water, which are most commonly used to quickly adjust the parameters of a cup of hand-brewed coffee.

Adhering to the principle of insurance, compared with the other two factors, the water temperature is generally our "constant" fixed value, either a lower 88 ℃, or a higher 93 ℃, or a median value of 90 ℃.

However, in the eyes of some brewing champions, water temperature can become a key variable for them to regulate the flavor of coffee, using two or three different water temperatures to flush in stages to achieve an ideal extraction model, which is also known as "variable temperature brewing". For example, the three-warm hand method, invented by Wu Zelin, champion of the 2016 World Barista Competition (WBC), is still favored by many players today, and Qianjie plans to reproduce it.

Why do you use multiple water temperatures to make coffee?

In previous articles, Qianjie always stressed that the higher the water temperature, the easier it is to accelerate the extraction efficiency of flavor substances in coffee, and the faster the sweet, sour and bitter components in each stage are released; on the contrary, the lower the water temperature, the more difficult it is for soluble substances to spread into the water, that is, the longer scouring time is needed to obtain flavor. The water temperature we often talk about actually refers to the value measured by the thermometer before formal water injection, that is, the initial temperature of the pot, and the whole process will decrease step by step with the room temperature.

In fact, coffee making can be seen as a process of regulating flavor molecules such as sour, sweet, bitter and astringent. According to the release fluctuation diagram of coffee flavor, sour taste and sweetness will dissolve in the front and middle, while mellow and bitter substances will release more in the latter.

If a relatively high initial water temperature is used in the early stage, the powder bed will be maintained in a high temperature environment, and the release of a large number of sweet and sour substances will bring higher flavor complexity to the coffee. Of course, at this time, some of the mellow bitter substances will come out in advance. Therefore, if you want to finally drink a balanced taste of sweet, sour, bitter and sweet, you have to reduce the water temperature to restrain the movement of bitter ingredients in the tail, that is, to prevent overextraction.

The specific parameters of the three-warm hand method

As the saying goes, if you want to do good work, you must first sharpen its tools. If you want to change the temperature of cooking, you must first be equipped with a container that can provide several different temperatures. Wu Zelin's three warm hand punching method, as the name implies, will involve three temperature values, which are 94 ℃, 90 ℃ and 80 ℃ respectively.

In terms of the distribution of coffee powder and water, he takes 16 grams of powder commonly used in the shop as the benchmark. The ratio of powder to water is 1:15 and is divided into four stages of water injection, that is, a total of 240g of hot water (40g, 80g, 80g, 40g).

Here, Qianjie plans to use 2 hand flushing pots + 1 room temperature kettle. First, pour the boiled water into two hand flushing pots, one of which will lift the lid to cool to 94 ℃, and steam the first stage + the second stage. The second pot of water is covered with a thermometer to cool down naturally, and by the time the third stage is injected, it will be almost 90 ℃. Then, add a small amount of normal temperature water (about 15~50ml) to the first hand flushing pot to make the last stage of water injection immediately after the temperature reaches 80-85 ℃.

In terms of grinding degree, contestant Wu Zelin did not give an accurate data, but asked everyone to judge according to their own total cooking time. Qianjie thinks that if the dripping time is less than 2 minutes, you can grind the powder finer, and if you brew coffee for more than two and a half minutes, you can consider grinding it a little thicker.

Qianjie here uses the honey-treated rose summer of Guatemala New Oriental, a medium-to-shallow roasted coffee, which tends to express sweet flavors such as toffee, orange and cocoa biscuits, so it will be ground with the daily fine sugar produced in the store, that is, the commonly used No. 20 sieve has a pass rate of 80% (the scale of the EK43s bean grinder is 10). As for the filtering apparatus, Qianjie intends to use the Hero variable speed cake flat-bottomed filter cup, which was started not long ago, to provide the function of temporary soaking at the end.

It's not too late. Start cooking right away.

For the first stage of steaming, pour 40 grams around with 94 ℃ of hot water and steam for 30 seconds. Before injecting water, make sure that the cake filter cup gear is dripping at a uniform speed. )

At the end of steaming, continue to use the high-temperature water just now to inject 80g of the second section with a large flow and a slow circle rhythm, so that the powder bed is raised to the height of 2cm and 3 of the filter cup.

When the coffee liquid in the filter cup is almost all dripped, you can pick up another pot of 90 ℃ hot water prepared in advance and begin to inject into the third stage. The same way that the flood flows slowly around the circle is injected into 80g. After injection, the liquid level will just reach the height of the powder layer formed in the previous second stage.

While the coffee liquid in the filter cup is still being extracted, we add a small amount of normal temperature water to the high temperature pot so that the thermometer value falls to 80 ℃, ready to start the last injection.

After all the coffee liquid flows into the lower pot, turn the knob of the filter cup into soaking mode, pour the remaining 40 grams of water into the powder layer, soak for 20 seconds, and finally open the valve to let it all flow into the lower pot. The coffee dripping time is about 2 minutes and 18 seconds.

Finally, Qianjie tasted a very prominent taste from the New Oriental Rose Summer, which adopted the three-warm brewing method, with solid and rising citrus acidity, a hint of chocolate and the sweetness of dried cranberries, accompanied by a sense of freshness. it's a very comfortable cup of coffee.

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