About Espresso

Espresso from the first class, teach you how to press the cake, how to observe the flow, and then tell you how to be a qualified espresso.

Today, the learning of espresso is still based on these basic parameters, but it is more closely related to its own senses.

Here, nothing really new is just making a little summary for himself and looking back from the needs of feeling. Why should we do this?

Espresso-30ml highly concentrated liquid, let people in the mellow fullness (body) feel sweet (sweetness), sour (acidity), a variety of beans flavor (characteristics, notes), and coffee is a very interesting thing, its planting process, baking special so that we can not find an almost perfect balance. Perhaps, we can feel mellow, but too mellow coffee is often based on the price of absorbing flavor, maybe we like to feel the jump of taste buds in sour taste, but too much sour taste will not only make people feel pungent. What's more, the sour taste will make the milk foam unable to stabilize for a long time.

Admittedly, for a barista who has chosen the beans, he cannot control the flavor of the beans in percentage. With a little bit of frustration and irresponsibility, baristas are less able to control the fate of coffee than roasters and farmers. But it is undeniable that the same coffee beans, different baristas' understanding and skills of coffee can make completely different coffee. For me, under the premise of inherent equipment and coffee beans, the practice of barista cooking under rice is the most interesting thing. And through this period of time, what kind of feeling and what means to find some more direct connection. That is, what we might be able to do for such a flavor.

Previously mentioned the sensory balance, that is, acidity, mellow mutual common, plus the embodiment of flavor. To achieve this, we all know that it is through about 20g of coffee powder, through high pressure, high temperature water through about 30 seconds to complete two cups of about 30ml espresso. (the value I said is for relative reference only, not an absolute value, it depends on coffee machine, coffee freshness, etc.)

For most machines, what we can't change is the water temperature and pressure (of course, slayer, starada individual machines are achievable), so we don't want to be perfunctory here.

But as a barista, what can be changed is the amount of powder, the degree of grinding, and the strength of the cake. At the same time, it should also be combined with one parameter, that is, the freshness of coffee. With the extension of coffee storage time, the effect of extraction will naturally be different.

Then in the notes sorted out later, around how to control the extraction of their own espresso, more exploration and thinking will be made in the integration of grinding degree, powder quantity, cake pressing strength and coffee bean freshness.

Hot water of about 90 degrees is ready to infiltrate pressed powder at 9 atmospheric pressures. The closed pressed powder and the carbon dioxide in the cake with various flavors create great resistance to the infiltration of aquatic products.

This process led to a result, a result that we didn't see at the beginning. The flavor in water and carbon dioxide merged, and at the same time pressed powder began to expand and be permeated by water. At the same time, the taste of the main body of coffee began to release gradually. And this release process determines another parameter of espresso. Fullness.

To simplify, among the two flavors in our taste, sour (and flavor) and fullness (more, bitter), sour is dissolved with water first, that is to say, sour should dissolve fastest with water. Bitterness, on the other hand, is released in a more uniform way.

In the process, the water is still looking for a way out in the coffee pressed powder. And the first batch of water will absorb all the original substances of coffee, which is not only flavour, but also body, but also sugar. More importantly, only by absorbing these ingredients can the later water find a way out (I would love to use the word passageway. But it will confuse channelling)

At the same time, it is worth mentioning that the water still stays on the surface of pressed powder. And the surface layer is the largest part of our pressure on the cake. It is also the most tightly structured process. (conversely, the bottom layer of pressed powder is almost unaffected by tamping. La marzocco has experimented with forces ranging from 5kg to 50kg, with little difference at the bottom. This is also the reason why the automatic cake pressing force on their grinder is very light.

Therefore, at this time, the amount of powder in pressed powder has not yet had an effect on the composition of coffee flavor, but directly related to the coffee flavor is the thickness of grinding. The reason for dissecting here is that there is a very important topic: relatively fine grinding + less powder.

Relatively coarse grinding and more powder.

Even if the two cases can extract 20-30ml in 30s, the flavor will be completely different. In the first stage, the fine pressed powder will stay a little longer, and the most flavor, sugar and acidity will be obtained.

Here is still a small summary around the parameters mentioned in the first chapter.

The thickness of grinding for 3-6 seconds in the first stage almost determines all flavor and part of plumpness.

But it should be said that the fullness here is "insignificant" relative to the long time of 30 seconds.

The amount of powder has almost no effect on the strength of the cake pressing-the resistance produced by the surface.

Determines the initial stay time of the water on the surface, the freshness of coffee.

-the fresher, the higher the carbon dioxide content, the longer the baking time, the higher the carbon dioxide content, so the greater the resistance.

The coffee is about 5 seconds and has begun to flow out.

The coffee extracted at this time should be the part with the highest concentration and the first part of the coffee to be extracted.

But how does this part taste? We all like the coffee that has just been extracted. Not all the squeezed amber will be delicious.

If we test it with a concentration meter, the TDS will be as high as 25%. So what does that mean? The coffee we drink will be extremely strong. But the main manifestation of strong is not bitterness?!

It is not that the bitterness of the coffee is not there, but that the acid-dominated flavor absorbed in the early stage far suppresses the bitterness. And we see that the amber color like ink retains the original flavor of the initial extraction, but like a good base liquor, its strong feeling makes it impossible for us to really identify and analyze its specific taste.

At this stage, the part of the coffee we drink is actually absorbed in the first four seconds, while what happens dynamically is a steady stream of hot water that continues to seep into the coffee pressed powder at nine atmospheres.

Due to the early extraction of most of the upper end of pressed powder, at this time the water gradually invaded the lower layer of pressed powder. And pressed powder is the lower the structure is looser, the resistance will naturally be less and less.

This can also explain why it began to accelerate like the silk of honey falling from the building. Strictly speaking, the efficiency of extraction will become weaker and weaker at this time, because the loose pressed powder structure of coffee shortens the residence time of water per unit time, and in the process of attenuation of flavor absorption, the bitterness of coffee "passes by" in the acceleration of water.

The thickness of the grinding in the first 4-10 seconds of the second stage-most of the initial flavor has appeared in the first 5 seconds but begins to decay.

The amount of powder-the amount of powder determines the thickness. The rate of change in color means the amount of powder. Because too little powder will prematurely let the hot water open the road. Thus reducing its plumpness.

The strength of the cake pressing does not matter, because the powder is pressed through the top layer of the powder press, and the powder with the closest texture has been passed by hot water.

Coffee freshness-still has an impact, the fresher, the higher the carbon dioxide content, the longer the baking time, the higher the carbon dioxide content, so the higher the expansion, the greater the resistance.

It should be reminded here that too much carbon dioxide in the process of hot water will affect the stability of the extraction. We can see that very fresh coffee produces large bubbles in the process of extraction. This will cause uneven extraction between the left and right sides, even if our pressing powder is correct.

The outflow part is the thickest original pulp in the first 5 seconds. A collection of all flavors, but too strong to be imported.

The hot and high-pressure running water has completely penetrated the pressed powder. While pressed powder absorbs enough energy and begins to release its own soluble matter, the resistance it produces gradually decreases. And this part, that is, about 12, 13 seconds, we will see that the color of the coffee will gradually fade.

If the coffee is fresh and contains plenty of carbon dioxide, we will put less powder, the color will change quickly, and the outflow rate will increase very fast.

On the other hand, if the coffee has been two weeks later, a lot of carbon dioxide has evaporated, we have more powder, the color changes relatively slowly, and the flow rate increases slowly. This phenomenon also explains why espresso requires a soothing process.

Because excessive fresh coffee is bound to reduce the amount of powder, the reduced amount of powder brings about a rapid change in color, which means that the mellowness of the coffee will be greatly reduced.

More academically, the reduced amount of powder means that a cup of 30ml's espresso extractable material is naturally reduced.

By about 15 seconds, we can see that the brown color begins to fade and turn yellow.

And the barista is about to concentrate on color change during this period. This link is very important, because at this stage, we can still get a very high concentration of coffee, cut off, which means that this is a cup of ristretto.

Because of the combination of the previous high concentration, its flavor is often very rich, and the main acid.

Of course, if it is closed at this time, it should be restretto.

In most cases, a serious barista is waiting for the moment when brown turns to gold.

According to experience, it should be a more balanced espresso. Of course, this is not absolute, for example, this cup of coffee is deep-roasted and the color itself is darker at first. Or it is light baked and needs to make cappuccino, which needs to leave some yellow to compensate, or coffee and fresh, less powder, need the yellow behind to compensate for the sour taste.

However, in the normal course of operation, that is, about 23-28 seconds, the barista will choose the right time to cut it off.

And, responsibly, with each second extension, the flavor of the coffee will be a little different.

By this time, the pressure of the powder does not matter, and the thickness of the grinding is not so important because the channel is fully open.

The only thing that determines the flavor of coffee is the gram weight of the powder. At this time, if the amount of powder is more, we will get a thicker espresso, if the amount of powder is less, our consistency, or mellow feeling will be weakened accordingly.

(thinking about the problem, there is too much powder, in order to maintain a normal flow rate, grinding is bound to be thicker, which means that the flavor of coffee may be weakened.)

The color begins to fade, and the barista will cut off the espresso at the right time according to the taste.

The picture of the album is easy for everyone to understand.

At this point, a flashback of espresso has completed its beginning.

Because when a cup of espresso you really like is presented in front of you, please cherish it. It's not just about cherishing the focus of the responsible barista, not just the baker's research and work on blending and baking, and the hard work of coffee farmers.

More importantly, this whole set of value addition chain is not really adding value, but to preserve the soul that nature has given to these about 50 coffee beans.

Citrus flavor, plum fruit flavor, or vanilla, cream, syrup, cocoa and so on, these are not created by human labor, these are the gifts of nature.

This is precisely the reason for our humility. That's why I mentioned soil, heat, and water in the coffee common sense group. The flashback of espresso has been completed, but the road to coffee has only just begun. Because its existence requires our senses.