The thinking mode of extraction uniform extraction of fine coffee

We talked about some of the connections between taste and data in general. The core idea is the relationship between alcohol thickness and TDS concentration, and the relationship between sour, bittersweet and extraction rate.

If we set out the goal in the first chapter, then the goal we want to achieve is mainly the following two points:

1. A reasonable extraction rate of 18-22% was obtained. Because this can achieve a balance between sour and bitter, even sweet taste.

two。 Obtain the proper concentration of soluble matter, Espresso between 8-11%, hand-brewed coffee between 1.15-1.35% (SCAA standard)

Of course, this is more conceptual. Because we assume coffee beans, there is no obvious flaw in the roasting itself. The two basic goals that need to be achieved. Maybe here, someone will ask, "doesn't the temperature of the water matter?" "the utensils used are also related to the taste of coffee!" I will elaborate on this kind of problem later. because they are not the end, they are still the means to achieve the above two points.

Then, according to logical discrimination, we need to find the parameters that have a direct impact on the extraction rate and concentration through a systematic classification. After a certain amount of time, I personally classify it into three modules:

A uniform extraction

In the process of extraction, whether the coffee powder is given the same proportion of soluble matter in contact with water.

B extraction time

How long is the contact time between coffee powder and water in the process of extraction?

C and extraction efficiency

In the process of extraction, whether the external parameters or the coffee itself change the extraction of soluble matter per unit time.

Here, please sort it out carefully. Let's not talk about what kind of coffee is made. As long as it is extraction, we choose the amount of powder, water temperature, steaming, and so on are nothing more than these three modules. In other words, in the face of the rapidly changing trend of coffee and dazzling brewing methods today, in order to find a reasonable extraction rate and concentration, we need to know whether our extraction method has improved uniform extraction, or changed the extraction time, or extraction efficiency. If we sort out these concepts, we will master a scientific learning method.

Today, I would like to start with uniform extraction.

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A uniform extraction

In the process of extraction, whether the coffee powder is given the same proportion of soluble matter in contact with water.

It is not difficult to take it literally. But in real life, cup testing, or tasting extraction is not uniform is difficult. Because if we drink a cup of sour coffee, you might think that coffee is not extracted enough. If you drink miscellaneous odors in the later stage, it may be excessive extraction. But sometimes, coffee is not sweet, and sour and bitter imbalance, sour, but also mixed taste. We will be confused as to whether it is the problem of beans, baking or making it ourselves. Believe me, sometimes even the best baker, cup tester, may not promise to find the root of the problem immediately. (beside the point, it doesn't make much sense to argue about the taste of coffee on the Internet.) however, compared with roasting and re-examining raw beans, adjusting the extraction method to evaluate the effectiveness of coffee is also a necessary first step for the blending of coffee beans themselves. (beside the point 2, it is immature to draw conclusions about coffee beans without several attempts at extraction. On this topic, an article about the fault tolerance rate of coffee can be found in http://site.douban.com/widget/notes/2050537/note/244363881/. Some coffee is really not easy to make.

So which will affect the extraction uniformity, such as uneven pressing powder, resulting in high pressed powder on one side and low pressed powder on the other. Pressed powder is high, if the water is uniformly permeated down, the part with more natural powder will be underextracted, and the part with less powder will be overextracted.

For example, when the hand is flushing, the gesture results in too much water on one side and less water on one side, or only a small piece of water is injected into the middle. So it is conceivable that less water will lack extraction, while more water injection will lead to excessive extraction.

Many friends know that hand coffee needs to be steamed. Interestingly, when I am in training, I often ask 3-4 questions, and often many friends get stuck on the third question:

1. Why are you steaming?

Because the coffee is fresh.

two。 Why does fresh coffee need to be steamed

Because you have to let it expand for a while.

3. Why does it expand?

Because it's releasing carbon dioxide.

4. Why do you have to steam a lot of carbon dioxide? (at this time, I will be careful to add that it is not my fault.)

A lot of friends have been asked here. Because a considerable number of them did not expect that carbon dioxide is not easily soluble in water, hindering the contact between water and coffee.

Of course, this is only an example, and it needs to be proved that many of our production methods are indeed related to the uniformity of extraction. More importantly, such cases are not backed up, but need to be thought about. Sometimes different ways of making coffee have a good framework, and even can be used for reference.

If we take steaming as an example, we will understand more or less:

1. The preinfusion (pre-embedded function) of E61 actually has the effect of steaming, first fine water flows for a long time, so that low-pressure water is powdered and carbon dioxide is emitted.

two。 Then, pre-embedding has more practical significance for fresh coffee.

3. Today's variable pressure espresso, we can at least simulate E61, first low pressure and then high pressure to achieve the purpose of uniform extraction of fresh coffee.