Hand-steaming coffee steaming skills hand-steaming coffee steaming without hamburgers? steaming failure?

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What are "steaming" and "hamburger" in hand-brewed coffee?

[steaming] in English instructions, it is often expressed as Bloom, which refers to the preparatory action of wetting a small amount of hot water evenly on the surface of coffee powder during hand flushing before formal water injection.

Steaming is a very important step in the process of making hand-brewed coffee. Good steaming can fully infiltrate the coffee powder and activate the coffee activity, thus making the coffee extraction process more smooth. Some stuffy steams with obvious steaming effect and large exhaust capacity will make the coffee method bulge in the shape of [hamburger]. Generally speaking, for beginners, the effect of steaming can be judged by observing the shape of "hamburger".

The effect of steaming coffee by hand

First, in order to release the gas in the coffee particles, mainly carbon dioxide.

When coffee is roasted, when it goes through a high temperature (at least more than 160 degrees), the gaps between the internal fibers of coffee will become more and more loose and more and more, and these fiber gaps often hide a large amount of carbon dioxide and other gases produced by the chemical changes of coffee beans during roasting, and most of these gases are mainly inert gases, so even if exposed to air The gas in the coffee beans is not immediately released and diluted by the air. Even if it is ground into powder, although the beans will be ground open during grinding, there will still be gas in some of the fiber gaps.

Therefore, when brewing begins to enter the water, the coffee powder will absorb water, and the water will gradually fill these voids. When the fiber gap in the coffee is really filled and the gas is discharged, the powder ball will be considered to be in complete contact with the water. Ready to release effective substances.

Second, in order to make the coffee physical expansion, form a uniform gap, and then form a good filter layer, so that hot water can pass through quickly and evenly, will not be excessively blocked, resulting in excessive extraction, and then full extraction.

Because the density of water is higher than that of gas, the gas in the fiber of the powder is always discharged to the outside of the powder, but because the water originally has a certain tension, and the coffee also has the release of soluble substances, which further strengthens the surface tension of the water. and the powder floats on the surface, further reducing the distance between water molecules, in disguise also increases the surface tension, the gas can not pass through the surface of the powder layer at once. But after the water is absorbed by the coffee powder, more and more gas is discharged, and the hamburger expands more and more.

How to steam the coffee by hand correctly?

Main points of details:

1. Before steaming with water, make sure the coffee powder is as horizontal as possible in the filter screen or filter paper.

two。 When steaming, the force of injecting water is not too strong, gently, try to wet all the coffee powder evenly.

3. When steaming, the water should be evenly distributed on the coffee powder, not directly on the filter paper. If the water is poured directly on the filter paper, it will make the filter paper fit with the filter, the heat will break through the coffee powder layer, form a hole, the cold air will enter, and the process of steaming will be destroyed. the good taste of coffee is not so easy to extract.

4. The amount of water used in steaming is 1.5 to 2 times the amount of powder, depending on the water absorption of beans. In the case of 15 grams of coffee powder, the amount of water needed for steaming is about 25 to 30 grams.

5. In the process of steaming, there is as little extract as possible; when there is too much extract in the kettle, the amount of water injected should be reduced, or attention should be paid to the degree of grinding.

6. The steaming time is about 20 seconds to 40 seconds, depending on the freshness and roasting of coffee beans. When the expansion of the coffee powder surface is over and the surface is about to shrink, it means that the steaming is complete and the first water injection can be started.

The necessity of steaming hand-made coffee

The splendor of hand flushing lies in its unrestrained and unrestrained imagination, and many people must have wondered: does hand flushing have to be steamed?

No, no.

My answer is: whatever you want.

It is a fact that there is gas in the powder fiber that will affect the uniform contact with water, but at the same time, it is not necessarily just a defect, because there are gases and gaps in the powder layer, the density will be relatively low and the buoyancy is high, and the powder has just released gas. between the powder and the powder, it is like a cushion with a layer of gas. when speeding up the water and increasing the flow of water, the effect of stirring can be increased, although the contact time between the water and the powder ball is reduced. However, stirring will increase the concentration difference between coffee extract and coffee powder, which is equivalent to enhancing the efficiency of extraction on the other hand, and can also achieve the effect of steaming.

Therefore, shortening the steaming time, or directly not steaming, in some cases is also possible.

The premise, of course, is to change the method of extraction. Such as stirring...

Portal: [hand-brewing coffee skills] how to stir to make your hand-brewed coffee taste better?

The relationship between steaming time and extraction rate

The role of steaming mentioned above, in fact, mainly summed up in one sentence: improve the extraction rate.

So, what is the relationship between the steaming time and the extraction rate?

The issue is very complex and involves:

The main results are as follows: 1. Steam exhaust can improve the extraction efficiency and extraction rate.

2. The loss of temperature of steaming powder layer and the decrease of boiling water temperature lead to the decrease of extraction rate.

3. The steaming is too long and the powder layer collapses. The gas in the powder layer is completely removed, which can not improve the extraction effect.

4. Steaming lengthens or shortens, which affects the whole extraction time and extraction rate.

……

Generally speaking: with the increase of steaming time, the flavor showed that the acidity decreased, while the sweetness and stickiness increased. The overall flavor gradually moved backward, and more complex. The overall extraction rate increased at first and then decreased, and finally decreased gradually.

Specific experiments can be seen:

So, let's get back to our theme: why doesn't some coffee swell when steaming, or even "hamburgers"?

The factors affecting the degree of steaming expansion:

1. The freshness of coffee beans.

As mentioned earlier, steaming is for exhaust, so the fresh coffee beans contain more gas (mainly carbon dioxide), and the more "hamburgers" swell when steaming naturally. If you don't see an expanding "hamburger" during stewing, it means that the coffee may have been roasted for too long, causing the carbon dioxide in the cells inside the beans to be released naturally, which means that the beans are no longer fresh.

2. The roasting degree of coffee beans.

To a certain extent, the deeper the roast, the more obvious the breathing effect of the coffee beans, the more gas will be released, and vice versa. For a lightly roasted bean, the caramelization (or carbonization) is not as deep as the deep-roasted coffee, and the reaction produces fewer metabolites (released gas), so the respiration is weaker, so it is normal that the steaming effect is not obvious or there is no "hamburger" effect.

3. The grinding degree of coffee powder.

It is not difficult to understand that if the grinding is too rough, the surface area of water in contact with coffee powder will be small, and the exhaust effect will naturally be weak. if the grinding degree is particularly rough, there will be no "hamburger" in any case.

Why do hamburgers always collapse quickly?

1. Oversteaming

2. Excessive water injection after steaming.

3. Bean baking is relatively shallow.

It collapses soon after steaming a hamburger, which should be related to the technique, such as strong water injection to break the powder layer or too much water injection. Steaming and injecting water is best to draw a circle from the center; when steaming, the amount of water is too little, the coffee powder at the bottom and edge of the filter cup is still dry, and when reinjecting water, it is especially easy to produce large "volcanic bubbles" when it is hot.

Last

It can be seen from the above that whether there is a "hamburger" in steaming has nothing to do with the taste of coffee. Of course, many people like to quietly watch the steaming "hamburger" slowly transpirate and expand when they flush their hands. This is a kind of inexplicable but real "spiritual sustenance", as if as long as the steaming is good, the "hamburger" is beautiful, and this cup will certainly taste good; if the steaming is not done well, then I am sorry. This cup of hand has been ruined.