If the target liquid weight cannot be extracted through concentration, can I press the extraction button again? Is secondary extracted espresso good?

When we extract espresso, we always extract the target liquid in one breath. But sometimes, we may end the extraction of espresso early because of a moment of carelessness or mistouch.

Although this can be called Ristow, as Qianjie said, none of the espresso except Australia and White will be made on the basis of Ristrido. Therefore, when this happens, if we want to get a suitable latte and American style, we can only obediently re-extract an espresso. However, some of the more imaginative friends will begin to think: since there is not enough extraction, can we press the extraction key again and do a "segmented extraction" like hand-brewed coffee?

Can concentrated extraction be divided into multiple times? Well, since you want to know so much, Qianjie will come and practice for you! In this experiment, Qianjie will extract three concentrated parts, namely, one cup of normal extraction and two cups of segmented extraction. The espresso extracted by two cups of segmented extraction will have different cut-off nodes to see what different flavor the concentrated coffee will have at different nodes, and whether the extraction of espresso can be divided into two times!

The coffee beans used in this experiment are still warm sun blending. after all, there is only one Italian mill in Qianjie, and then grind it to the 1.2th scale of Galileo Q18, with a powder-to-liquid ratio of 1:2, that is, 20g powder, to extract 40ml espresso. First extract a regular concentrate! As the extraction is done in one breath, the extraction time is very conventional 30 seconds. The flavor is still warm classic whisky, butter cookies, and slightly sweet and sour berries.

Then there is a secondary extraction concentration! We stopped the extraction when it reached half of the target liquid volume, the extraction time was 20 seconds, and then restart the extraction at an interval of two seconds. as a result, the remaining 20ml was extracted in just 4 seconds, the color of the coffee liquid was very light, and the total extraction time was 24 seconds. On the other hand, the taste of this cup of espresso is very thin, with a flavor, but not obvious.

Finally, there is a concentration near the end! Qianjie stops extraction when it reaches 2 / 3 of the extraction, and the parameter at this time is 25 seconds, 31ml! Then reopen the extract at an interval of two seconds! Similarly, the remaining 10ml liquid was extracted in as little as two seconds. This concentrated cup is not so thin compared to the second cup, it will be thicker and more full-bodied. But this can only be compared with the second cup of coffee which is seriously underextracted, and its expressiveness is relatively weak compared to the first cup.

So we can know that if the extraction is stopped by mistake during the production of espresso, it will be difficult to extract the rest of the coffee completely even if it is started again. The reason for this situation comes from the unique extraction method of Italian coffee machine-pressurized type!

Pressurized extraction when we activate the extraction key to make the concentrate, the espresso machine begins to operate, providing 9bar pressure to force the substance out of the coffee with hot water. This pressure will push pressed powder down and compact, thus increasing resistance and making the distribution of hot water more uniform! At the same time, the moment the hot water came into contact with pressed powder, a large amount of carbon dioxide filed out, squeezing the space and also hindering the flow of hot water. Therefore, in such a space, hot water can only be "humble" slowly downward infiltration. But if we stop the extraction halfway, the originally saturated spatial structure will be broken. The recoil suction of the cooking head absorbs all the material from the surface of pressed powder, and the density of pressed powder is changed after extraction. As a result, the factors that could have hindered the flow of hot water are gone, and the hot water released by restart can quickly seep out directly from the channel of the powder bed. Too fast flow rate is bound to prevent hot water from fully extracting coffee, so the color of the large amount of coffee liquid released in just a few seconds is so thin.

Then this kind of coffee liquid will not only produce bitter taste more easily because of the channel effect, but also cause the original extracted espresso to be diluted because its concentration is too low. Therefore, when we are on the way to extraction and concentration, if the extraction is turned off by mistake, then it is best to reextract an espresso instead of secondary extraction on the same pressed powder. Lest the final cup of espresso, which is full of instability, will destroy the final wonderful coffee experience.

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