Coffee machine common sense Italian coffee grinder data collation 2

There are more words described here, which will be boring compared with the evaluation of coffee and flower drawing in the past. But as far as I understand it, it is the most important part of coffee extraction.

At the same time, after writing this diary, it can be regarded as a paragraph on the exposition of coffee from the perspective of scientific theory. Not as a barista, this is the end of knowledge, in fact, there are many ways to improve the room for coffee. But through the summary of the past few years, this link is a return. It used to be from senses to data, but here it is to send data back to the senses.

Many friends know that if you look at whether the extraction is reasonable, it is mainly aimed at the flow rate of the extraction. Generally speaking, it refers to 30 seconds, 30ml (including creama)

The previous chapter described the various characteristics of the grinder. But in fact, in the end, it is necessary for the barista to adjust, that is, the two main parameters mentioned earlier, the amount of powder and the degree of grinding.

If:

1. If the amount of powder is more, the flow rate will be slow, because the more powder will provide more resistance.

two。 Fine grinding, the flow rate will also be slow, thinking that fine grinding will increase the density, thus reducing the gap and providing more resistance.

Here we can draw a conclusion that the amount of extraction can be controlled by adjusting the amount of powder and grinding degree.

But have you considered a very fundamental question here?

In turn

At the flow rate of 30 seconds 30ml, the degree of grinding and the amount of powder can be combined in different ways.

that,

Even if the flow rate is correct, the flavor may be different with different settings of grinding degree and powder quantity!

In fact, what I said is almost all the tasks of baristas. That is, in the case of a reasonable flow rate, through fine-tuning to achieve the due flavor.

In this process, in addition to the amount of powder and grinding, we do not put in the water temperature of the pressing powder and coffee for the time being, but to add another important parameter, that is, the freshness of the coffee. Because the fresher the coffee, the higher the carbon dioxide content, the higher the resistance.

Okay, let's sum it up again:

1. The amount of powder, the more powder, the greater the resistance.

two。 Degree of grinding, the finer the grinding, the greater the resistance.

3. Carbon dioxide, the same amount of coffee powder, the fresher the coffee, the greater the resistance.

Therefore, at the same flow rate, coffee at a specific time, we need to set the grinder, as well as more and less grinding to ensure that not only the flow rate is moderate, but also the flavor is more suitable.

Here are a few questions:

1. What kind of flavor is the more suitable flavor?

two。 Which taste of coffee is determined by the amount of powder, the degree of grinding and carbon dioxide?

3. How to adjust accurately?

Unfortunately, the first problem, although today's baristas have specific instruments that can be quantified by data. But in the final analysis, there needs to be a complete evaluation standard. This standard is not an absolute value, but a taste framework. I can't use words to describe how good coffee is. This requires everyone to practice face to face together. But in order to better describe the following article, I will temporarily take the two most important characteristics of espresso as indicators of whether it is well-intentioned concentration: richness and balance.

In fact, rich and balanced, in order to facilitate understanding, and then simplify it, we use body and flavor to reflect. Although many flavor have chocolate, syrup, etc., but most of the flavor will be mainly acidity, that is, sour taste. therefore,

The equilibrium mentioned here is determined by body alcohol and acidity acidity.

Relatively speaking

In the process of coffee extraction, the flavor is dissolved in the water at the beginning of extraction by high-pressure hot water. After that, the dissolution rate will have a large attenuation.

On the other hand, the alcohol content is a relatively peaceful and uniform extraction process. That is, the alcohol content will increase at a uniform rate with the time of coffee extraction.

In short, at the beginning of the extraction, the extraction of most of the flavor parts will be completed in the initial 5-8 seconds, and the longer the alcohol content, the higher the alcohol content. The extraction rate of general coffee will not exceed 40%.

[suggested experiment 1: if you have the opportunity to do an experiment, divide the 30-second extraction into three stages, the coffee will be very sour in the first 10 seconds, the taste will be moderate in the middle 10 seconds, and the coffee will be bitter in the last 10 seconds. ]

So back to what I said earlier, if you want to produce 30ml espresso in 30 seconds. The degree of grinding is fine, which means that the amount of powder should be relatively small. When the grinding degree is adjusted finely, the area of coffee in contact with water increases, which will improve the acidity of coffee. But what is sacrificed is the reduced amount of powder, that is, mellowness.

And then the other way around.

If the grinding adjustment is very thick, then in order to ensure that there is 30ml espresso within 30 seconds, it is necessary to increase the amount of powder. Therefore, it also means that although the density of coffee powder is reduced and acidity extraction is reduced, at the same time, the thickened pressed powder can increase its mellowness through layer by layer extraction.

Therefore, it is obvious that baristas can balance the taste by adjusting the amount of coffee powder and the degree of grinding.

Hehe, it's easy to say, but it's actually difficult. Because we haven't put in another parameter, coffee freshness.

If the coffee starts to make espresso as soon as it comes out of the oven, the huge resistance caused by carbon dioxide has to set the grinder to be thicker. Because if the setting is too fine, the amount of powder will be greatly reduced, and the mellowness of the coffee will be greatly reduced.

To take another extreme example, if a lot of carbon dioxide is emitted four weeks after the coffee is roasted, the grinding degree must be thickened to ensure that the flow rate is correct by increasing the amount of powder.

This is why it can be explained that espresso has a longer awakening period. It's not that the fresh coffee is better, but that we need a well-balanced cup of coffee.

It is recommended that in experiment 2, make a cup of coffee with perfect flow rate on the third day after a bag of coffee beans are baked. Then compare the flow rate after three weeks. If you adjust it, you can obviously see the difference in terms of taste, flavor, and setting.]

Through the setting of the grinder, we can adjust the thickness and powder quantity. So how accurate does the powder setting need to be? Generally speaking, 0.5g is enough to change its flow rate and flavor. As for the adjustment of powder quantity, sometimes the grinder with large cutter head only needs to tap gently with a powder hammer, and the change of thickness can also change its flavor and flow rate. What's more, each cup has to be made the same, so we need a series of methods and tools to help us achieve it.

What has just been described is actually the core topic of espresso in the world over the past decade, that is, the relationship between extraction and flow rate as well as flavor. Here we have to mention the contribution of the Australian coffee industry to the world coffee. Melbourne, in particular, was rated by the World Coffee Association as the country with the best coffee environment in the world this year. If you pay attention to the competitions in recent years, basically, Australian baristas can enter the top three in the World Barista competition. And careful friends can find that even if they come from different institutions and coffee shops every year, their methods are the same.

This is because many colleagues have conducted a series of studies and studies to ensure that what they are doing is the most scientific and reasonable.

I cannot describe the powder quantity and grinding control in detail in this chapter. Because if you go on, it's beside the point. But in the next chapter, I will focus on these popular methods of powder, partial powder and pressing powder.

And the focus of this article, as I said earlier, when we know the characteristics of the grinder and its function. We actually understand the purpose of the tool, and in the end, in order to present a satisfactory cup of coffee to ourselves and our customers:)