How does espresso taste sour? On the extraction standard of espresso coffee

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Espresso coffee extraction detailed steps Italian concentrated common sense

Espresso Extraction And Standards Espresso Extraction And Standards

Espresso extraction judgment plays an important role in a coffee shop that emphasizes coffee quality, because espresso is not like hand brewed, French press, or siphon brewed coffee, which can be sipped after brewing to confirm the flavor and quality of coffee, but it is the favorite drink of most coffee consumers.(such as latte, cappuccino, etc.), in order to drink a cup of excellent flavor cappuccino, in addition to the correct milk, almost perfect extraction of Italian concentrate is also indispensable, so the extraction of Italian concentrate needs to rely on other reliable information to help the barista judge.

The traditional Italian rule of judgment is nothing more than: 25 ± 2.5 ml of single espresso at 8-10 atm pressure, 7 g of ground coffee, 86-90 ° C water temperature, 20-30 seconds, or 50 ± 5 ml of double espresso at the same time and pressure using 14 g of ground coffee, usually using a double split filter handle common in most cafes (double portafilter), as long as the coffee obtained meets the above range, it is considered a cup of normal extracted espresso.

Later, the Specialty Coffee Association of America (SCAA) had a slightly different interpretation of espresso: a single 45 ml espresso was extracted at 9-10 atmospheric pressure, 7-9 g coffee powder, 88-92 ° C water temperature, and 22-28 seconds. However, in practice, it will be found that such data is only for reference, because the degree of roasting of coffee and the understanding of coffee flavor in the past are far from those in the past ten years. In the past, deep-roasted formulas dominated the market. Espresso coffee with emphasis on nuts and cocoa flavor was popular. If the water temperature was too high, it would extract the bitter flavor. There was a slight difference between the current 93-94 ℃ for light and medium roasted coffee. In addition, the manufacturing technology of coffee machines has advanced rapidly in recent years, and the pressure curve can be changed and emphasized. Coffee machines have been invented one after another, and the brewing pressure is no longer a fixed 9 atmospheres, whether it is pre-soaking pressure. The introduction of pre-infusion or gentle ramp out of pressure, a variety of pressure curves beyond the old rules have been tested and tested, even the same coffee bean, under different pressure curves, the performance of flavor spectrum are different.

In the third wave of coffee revolution, advocates based on science coffee people, in addition to narrowing the reasonable range of normal extraction, but also increased a lot of standards to help judge good or bad, think that under normal circumstances, Italian concentrated extraction should use 18 g coffee powder, obtain about 30 g liquid weight, water temperature 92-94 ℃, extraction time falls in 25-27 seconds. It can be noted that the judgment changes from the volume of coffee liquid to the actual weight of coffee liquid, which is more accurate. This reason is that coffee can affect the amount of crema due to various factors such as brewing pressure, roasting depth, freshness, etc. If it is judged by volume, it is very unreliable. The water temperature also rises to 92-94 ° C due to the lighter roasting of the coffee in the third wave. In addition, the invention of the bottomless portafilter also allows baristas to observe the extraction status of coffee throughout the process, and if problems such as uneven extraction, channeling, and premature whitening occur, they can quickly refill the coffee before serving it to the customer. Since I started working with espresso machines, I have been fortunate to have almost always used bottomless handles to extract espresso coffee, giving me the opportunity to observe the extraction of each cup of coffee, and therefore a lot of learning opportunities.

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