What hinders coffee extraction? Principle and Application of Coffee extraction

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Perhaps the most annoying thing about making coffee is how to extract it better. Whether Italian or hand-brewed, baristas or coffee lovers are most concerned about extraction, so what factors prevent us from extracting a good cup of coffee?

Italian extraction

With regard to Italian extraction, Qianjie Coffee has talked to you before, such as whether there is caking in the grinding of powder, pay attention to filling gaps when laying powder, pay attention to average force and how to adjust when filling pressure, and so on. But when it comes to pressure extraction, sometimes instability leads to differences in coffee quality. why?

1. Do you care about your coffee machine?

If the Italian coffee machine you use is a high-end machine, many problems will not arise, but the performance of many general commercial models actually depends on luck. after all, coffee machine parts may be imported, but if the domestic assembly technology is not good, you may not be able to concentrate with good quality. The editor once used a commercial Italian machine, and the copper block in the head was not installed properly. As a result, the water leaked on the side, so the editor had to fill more powder to the side of the flow every time to balance the extraction. of course, this is only an expedient measure, and it is the coffee machine problem that hinders our extraction and concentration.

two。 Your pink hammer.

Powder hammer is your powder pressing weapon, whether constant pressure powder hammer or traditional powder hammer. But the pink hammer is not easy to use, even if it is compatible with coffee maker manufacturers. You can take a look at the following picture

A little too much indentation in the use of powder is a problem, but more importantly, the powder hammer does not match the powder bowl-you can see that there is a layer of coffee powder in the outer ring. Although most of the powder bowls on the market are 58mm in diameter, a slight error in the powder bowl, or the failure to buy a powder hammer that is the most suitable for the bowl diameter, will cause some coffee powder to be unpressed, making it easy to extract.

3. pressure

The pressure 9bar shown by most coffee machines is actually the boiler pressure, not the pressure acting on pressed powder during extraction (some high-end coffee machines have this function), but also because of technological problems, some coffee machines will "spray water" (excessive pressure) at first, and then suddenly become tired after a few seconds, so such a coffee machine will of course prevent us from extracting normally. If you often have coffee in Italian concentrate at the beginning of the normal flow rate, and then the coffee night suddenly turns white or the liquid column is unstable, the rest of the problem may be the water pressure output of your coffee machine.

Hand extraction

The editor believes that a uniform and complete extraction in hand extraction is the most important. This is the "framework" obtained from making espresso. By understanding this "framework", we can better understand what factors are hindering our hand extraction.

1. Is the coffee ground well?

Although we have reference (fine sugar) and data (correction sieve), the editor thinks that the most important thing is the uniformity and fineness of coffee powder. Because many friends (including editors) use domestic ghost tooth mills, once again, because of technological problems (it seems that our technology is really not very good), the degree of grinding provided by the coffee bean shop is not good enough to our machine, even if adjusted according to our own mill, there may still be problems such as the flow rate is too fast / too slow, fine powder blockage and so on. If the flow rate is too slow, although we can improve it by adjusting the grinding degree, the fine powder is not reduced and the uniformity gap is larger, which will cause the extraction state of the coffee powder to be more inconsistent during the extraction. then the coffee will definitely not taste good.

two。 Filter paper

The material of filter paper is a problem, and another is whether to wash it or not. In the past, the log pulp filter paper had the smell of wood, and then the white filter paper would add whitening agent or even fluorescent agent to make the product look better, so the filter paper became a convention (the editor is from Guangdong, so he will have the ritual feeling of washing everything). But now good pure white filter paper still need to wash this step? My personal opinion is that if you want to wash, just wet it a little, instead of flushing it with a lot of water. The reason is that the filter paper is a wood fiber, excessive washing will change the permeability of the filter paper, which has also been mentioned in previous articles. In addition, if the filter paper absorbs water, the coffee powder will immediately absorb the water in contact with the filter paper, that is, begin to extract, which will cause the coffee powder extraction state to be uneven. So if you are worried that the filter paper is "not clean", instead of washing it, you might as well change a brand.

3. Time / powder-water ratio

The ratio of time to powder is of course very important in hand-brewed coffee, that is, because it is important, the editor finds that many friends pay too much attention to the changes in the numbers and ignore the extraction itself, which hinders our extraction. When making coffee by hand, do you focus more on the state of the water scouring the coffee powder bed or keep an eye on the time and weighing changes? Time and water supply for beginners certainly need a process of practice and familiarity, but the editor thinks that if you always think that "at this time, there should be how much water should be" is too tangled, and may also affect the stability of your current. For example, when you just go around the outer circle, you suddenly find that you have to go back to the center to do the final water injection, and suddenly "rush" into the center from the outer ring, this operation will lead to uneven extraction.

Finally, I would like to talk about the factors that hinder our extraction, whether it is Italian style or hand impulse-mentality, or thinking. People often think that something is "just like that" and then act accordingly. For example, if the Italian style is bitter, it is necessary to thicken the degree of grinding; if the hand is sour, it is necessary to lower the water temperature a little bit. Of course, this is true, but we should know that extraction is a process of "moving and pulling the whole body", and one amount will lead to changes in other quantities, that is to say, it is obviously impossible to adjust only one data and fix other data. In the extraction of coffee, especially hand brewing, it is advocated to pay attention to the coffee itself, in order to be able to adjust at any time to better extract coffee, not just to get the right number of coffee.

Pay attention to the coffee itself, look at the characteristics of various variables in the extraction with an open mind, and make dynamic adjustments, all the changes are to keep the high-quality products unchanged, then any factors that hinder the extraction will become the ladder of our progress.