Does the stagnant water after the powder bowl extraction of espresso has anything to do with the powder bowl and water distribution network? How to adjust the extraction parameters?

Friends with toy machines, has this also happened: after cooking, take off the handle and find that the whole pressed powder is wet, there is still a lot of stagnant water on the surface, and the pressed powder knocked out is not shaped like a mud lump.

Under normal circumstances, after the extraction of concentrated coffee pressed powder should be a relatively dry state, knocked out of the pressed powder should also be a relatively complete, solid cake fast. If the above wet, soft state, knitting water problems, it is not a normal phenomenon. Today, Qianjie Coffee will talk to you about what factors will cause the stagnant water problem.

The coffee powder is too fine.

Italian machine extraction is the use of hot water under high temperature and high pressure, when grinding is too fine, the gap between coffee particles and particles in the powder bowl will be greatly reduced, even if the coffee machine reaches the maximum pressure value, hot water is also difficult to extract flavor substances through these gaps. At the end of the extraction, there may be part of the water failed to pass through the powder layer in time, accumulated in pressed powder, there will be wet mud lump, or even stagnant water.

Usually the most obvious phenomenon of fine grinding extraction is that the pressure gauge has reached the peak pressure for more than ten seconds, but the coffee liquid is still in a slow dripping extraction state, and the extraction time is relatively longer.

Because the grinding is too fine to lead to stagnant water problem, it is good to find and solve very well, properly adding the grinding degree of coarse coffee powder can adjust this phenomenon.

Coffee beans are not fresh

When the beans are not fresh, it is difficult to judge the cause of the stagnant water in the powder bowl. This situation usually occurs in individual Italian players with a small amount of cups. Under the consumption of one or two servings a day, a packet of spaghetti beans may be used for a month, and the carbon dioxide in the beans is almost dissipated.

You know, like hand brewing, the Italian coffee machine will also steam the coffee powder during extraction, that is, pre-soaking. When the coffee powder contains carbon dioxide, it expands under the action of hot water and fills the gap between the particles; if there is little carbon dioxide left in the bean question, it will not expand, and the flow rate of the coffee liquid will be faster at the same grinding degree.

Usually the concentrated oil extracted in this way is not rich or even absent, it is very watery, and the problem of stagnant water in powder bowls occurs frequently. When there are conditions, it is recommended to choose fresh coffee beans.

Too much or too little powder

Usually the powder bowl we use has a standard that can hold the amount of powder, and different types of powder bowls can hold different amounts of powder.

If you simply want to concentrate a little higher and increase the amount of powder, resulting in exceeding this limit, it will cause a series of problems such as "the concentrated extraction cannot be extracted, and after the handle is removed, the surface of the powder bowl is wet, but the coffee powder at the bottom of the bowl is dry." there is a pile of coffee powder sticking to the water distribution network.

However, if the amount of coffee powder used is too much less than the standard gram weight of the powder bowl, it will lead to serious stagnant water in the powder bowl after extraction and, more extreme, a puddle of coffee water will be spilled when the handle is removed.

(when the amount of powder is lower than that of the groove)

We need to know that the coffee machine releases a column of water with pressure during extraction, and when the extraction key is turned off to stop extraction, the pressure relief valve opens, and a reverse pressure is formed in the sealed handle powder bowl to discharge the excess water from the pressed powder through the relief valve. But when you have too little coffee powder and the distance between pressed powder and vermicelli is too large, it is easy to form stagnant water in the bowl.

If you can't judge whether the amount of powder you use matches the powder bowl, you can take a look at a concave line of the powder bowl. After pressing the powder bowl, you can see if it can just reach the depression. If you are too high to explain that there is too much powder, and if you are too low, you will have less powder.

Qianjie coffee daily debugging extraction parameters, for example, Qianjie uses a 20g powder bowl, in debugging will not use more than 20g powder, if you need to use more than 20g powder, Qianjie will choose to slightly refine the grinding degree; when the flavor is close, sometimes choose to reduce the amount of powder by a few grams, but the amount of powder will not be less than 19.7g.

Purge head to relieve pressure

The brewing head has not been cleaned for a long time, or the cleaning is not thorough, and the long-term backlog of coffee grounds leads to the damage of pipe drainage or drainage function, resulting in too much water in the powder bowl after each extraction.

If it is not serious, we only need to keep the head clean and wash it regularly with a special coffee machine cleaner; but if it still cannot be solved, it is recommended to contact customer service for inspection and maintenance.

The pressure of the Italian coffee machine is insufficient or unstable

Insufficient pressure is a common situation in household coffee machines, when the pressure is not enough or unstable, the pressure gauge appears "repeated horizontal jump".

(for reference only)

The most intuitive performance is that the extraction column suddenly changes from thick to thin, which will cause the pressure check valve not to have enough pressure backsuction, and finally a large amount of stagnant water remains after the handle is removed.

-END-

Front Street Cafe

No. 10 Baoqian street, Yandun road, Dongshankou, Yuexiu district, Guangzhou, Guangdong province