Italian concentration practice | Analysis of Italian Coffee extraction practice | how to grind and press powder?

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The other day we shared how to make a good cup of espresso, and then we received a short video from a friend and asked some questions. Then I found that many people who make espresso do not know how to make adjustments according to the state of coffee extraction. Today, let the editor and you to a brief actual combat analysis to help you in the practical application of better extraction of Italian concentration.

First, let's take a look at the video uploaded to us by netizens.

First of all, let's analyze the Italian extraction state in the video. The coffee liquid "dripped" for quite a long time after the beginning of the extraction, it can be considered that the degree of grinding is too fine to block the passage of water. In addition, the coffee beans used by this friend are relatively fresh. Coffee exhaust is exuberant and grinding is too fine is the reason why the first stage of the extraction is abnormal.

Then continue to analyze the state of the coffee liquid. In the middle of the extraction, the left diversion port finally flows out of the water column, while the right side is still dripping. Moreover, there is a great difference in the color of the coffee liquid flowing out from the two sides, especially the dark color on the right side. This shows that the interior of pressed powder is uneven, and the reasons are 2mur1: uneven distribution of powder, more coffee powder in the right half than in the left half, higher density after compaction leads to uneven extraction on the two sides. 2: grinding problem, there are large lumps of powder more distributed in the right half of the powder bowl, the density of the powder will be higher than the loose coffee powder, resulting in insufficient extraction of some coffee and over-extraction of some coffee, the color of the coffee liquid will be very uneven.

Then let's take a look at the pictures of pressed powder and pink bowl that we asked to take.

According to this pressed powder, we can see that there is a lot of coffee powder on the side, which may be left after pressing the powder without cleaning, or there is another possibility: your powder hammer and bowl do not match. In addition, pressed powder indentation is very deep, indicating that the amount of powder is too much.

Then look at the powder bowl after deducting pressed powder. We have talked about how to judge the extraction problem before. The residual coffee liquid on the powder bowl like this is very dark, but the extraction is very serious.

Finally, back to the video, in fact, the 30-second video extraction is not over, the extraction time is too long, it is also the reason for over-extraction!

Through the above analysis, we can apply to the actual adjustment.

First of all, the amount of powder.

In order to get a stable product, a fixed amount of powder is necessary, otherwise your coffee will be strong and weak, and if there is more than one barista at the bar, then a fixed amount of powder is the first element of your consistency.

Each coffee machine matches the powder bowl will have a capacity standard, we will usually weigh the powder according to this standard. Whether it is too much or too little, a cup of incorrect Italian will be extracted, especially if too much powder is used, the ultra-fine powder is easy to be sucked back into the water distribution network and cause unnecessary damage to the machine.

And then grinding.

The state of the powder like the one above is not normal. If the powder ball appears on the quantitative automatic bean grinder, it is caused by static electricity and can be easily opened by finger poking. However, if the grinding is too fine, the knife head of the bean grinder is not cleaned for a long time, and the large unity block caused by the wear of the knife head of the bean grinder, please check and correct it one by one according to the actual situation. Of course, the relationship between beans will also have, the use of oily deep-roasted coffee beans, the problem of dough is inevitable.

The normal state of the powder should be like the picture above. If we are using the bean grinder and coffee machine for the first time, we can first grind a little to observe: fine the degree of grinding, and then adjust the size while grinding. It will be found that the state of the powder changes from large to small, and then to almost no powder, so generally speaking, the appearance of a small powder (static electricity) is a more appropriate grinding degree. You can try to make a cup of double concentration, and then adjust it according to the time of 25 ±3 seconds and the amount of extraction = powder × 2. Finally, remember to try to confirm the flavor!

Check the pressing powder

Why did you skip the cloth powder? Because we have talked a lot about cloth powder before, and the right cloth powder does not mean that the pressing powder is correct! This is a test of finger skill. The following is only for ordinary pink hammers.

Our habit is to use 3 fingers (thumb, index finger, middle finger), 3 fixed points to "touch" to determine whether the pressure is flat. But if you are a novice, there is a good way to check whether the powder is flat, although it is slow, but you can judge and adjust it intuitively. Please see the picture below.

After pressing the powder, hold the whole handle like this, and touch with 2 thumbs to feel whether the edge of the powder hammer is parallel to the powder bowl, and then make fine-tuning according to the height, remember that it is just fine-tuning and leveling, and you can't press it down with your thumb.

Finally, with a normal extraction video, you can pay attention to the time when the coffee liquid fell at the beginning, the velocity of the diversion on the two sides, the end time and the weight of the liquid.