Introduction to the three extraction stages of espresso what is the taste of espresso espresso

In the past, when sharing the knowledge of making espresso, Qianjie paid great attention to explaining the preparation steps before putting the handle on the head, such as cloth powder and pressing powder, which are operable and have a great impact on coffee.

After buckling the cooking head, turn on the cooking button and leave the rest to the machine. However, we must also understand how the coffee is extracted after pressing this button in order to adjust the better parameters.

The first stage: pre-soaking is similar to the steaming stage in hand flushing, first releasing a small amount of hot water to wet the coffee powder to emit carbon dioxide. In some older coffee machines, there may be no pre-soaking function, so the cultivation of Italian coffee beans is particularly harsh, and if the time is short, there is still a lot of carbon dioxide in the coffee beans, which will make the flavor of the espresso liquid weak and the fat rough.

Almost all coffee machines now have this function. The general operation process is to buckle the coffee handle and boil the head, and then release water without pressurization, which lasts for about 2-3 seconds and then stops. The coffee powder will expand and exhaust after absorbing water, so as to improve the follow-up extraction efficiency and stability.

In the pre-immersion water injection, there is no need for pressurization, because if you use the normal 9bar pressure for pre-immersion, then it is likely to break through the coffee surface powder layer, prone to perforation (channel effect). Another important thing about pre-soaking is time. The time of pre-soaking is related to the freshness of coffee beans. If the coffee beans are too fresh, it will take a long time for them to release carbon dioxide. Generally, the pre-soaking time is controlled at about 5-10 seconds, which can be adjusted according to the time situation. The electronically controlled coffee machine with pre-soaking function is relatively easy to operate, just set the number of seconds you need in the pre-soaking time, then you can achieve one-button extraction. If it is a manual coffee machine with pre-soaking function, then you need to manually control the pressure and the flow rate of water in the extraction head. The second stage: after the end of pre-soaking, we enter the main stage of coffee extraction, when the brewing head will release hot water under 9bar pressure to impact the coffee pressed powder, which is quickly dissolved by the wet coffee pressed powder in advance. Normally, after pre-soaking, coffee liquid will flow out after the head meter reaches 9bar.

At first, very strong sour substances are extracted first, then sweet substances, and finally bitter substances. If you intercept the front, middle and back segments of espresso with three cups respectively, you will see that the coffee oil in the front section is the darkest, brown and the richest, with a strong sharp sour taste, while the middle coffee oil is slightly lighter and golden, and it has better fluidity, the concentration is not as high as the first cup, and it tastes more balanced, while the oil in the latter section is thin, light yellow, and tastes light bitter and sweet. Like mugi-cha. The third stage: end the extraction of espresso when to end the extraction, depending on what criteria, time, or liquid volume, or observe the moment the oil is whitened to stop the extraction. Qianjie believes that the basis for the end is that when the oil is whitened, it is already telling you that the delicious substance of the coffee has been extracted, and you should stop the extraction. In many cases, we end before we even see the grease whitening, because grease whitening means that some unpleasant flavors have been extracted, but we don't know if this amount will affect the flavor. So it will generally avoid this risk and end ahead of time.

But ending early will also have another problem, that is, your espresso may be missing the end, the lack of the end of the coffee will be very strong, and the rhyme is short. Therefore, it is necessary to assist in judging according to the two parameters of time and liquid volume. Time is what we often call 20-30 seconds, this is not a rigid rule, just a reference standard. Even if it is a semi-automatic coffee machine with one-button extraction, in addition to the basic operation of powder pressing, you should also understand the extraction process behind your key. after all, this one-button extraction also needs to be set by people.