Automatic coffee machine grinding degree and coffee concentration

With regard to the extraction of Espresso, there are many introductions on the Internet and books, either too many theories or not enough details. Seeing that many beginners are asking questions about espresso, I dare to take a few photos and write a few words to introduce how I extract Espresso at present. If there are any mistakes in the article, please point them out.

Return to the golden rule of espresso, which has been passed down for half a century, "extract 1 ounce (about 30ml) of espresso (espresso) in 25-30 seconds at 9bar pressure and water temperature of 90-92 degrees Celsius."

Although this golden rule is still controversial in professional coffee forums in recent years, 9bar pressure is basically not controversial, so a bunch of coffee machines boasting 15bar or higher actually refer to the most high pressure of the coffee machine, which is of little significance, and is generally used to fool newcomers. Stable pressure and stable temperature are the criteria for measuring Italian coffee machines.

General coffee beans can be preserved for 3 months if they are unpackaged. There are also espresso beans, which extract espresso, which is rich in oil. There is also a need for a fully automatic special bean grinder equipped with a semi-automatic coffee machine. Very fine grinding. It is very likely that the extraction is insufficient due to the rough grinding. Espresso is a 20-30ml coffee rapidly extracted in 20-30 seconds by high temperature and high pressure.

If you are making your own espresso at home, it is recommended to extract what Espresso needs: a semi-automatic espresso machine, an Italian bean grinder, a powder press the size of your powder bowl, an electronic scale, a timer, an espresso cup (preferably with a scale), a brush, a towel, a bag of not too bad beans.

Let me say a few more words about beans. Many beginners buy cheap beans in order to practice. In fact, this does not help you improve your extraction skills, because the extracted coffee is not good, and you cannot tell if it is your machine problem, or your technical problem, or the bean problem. So, a bag of similar beans can at least let you know that this cup of coffee is "bad", not because of the beans, and then find other reasons to narrow it down as much as possible.

A good concentration of extraction cup requires stable pressure, suitable water temperature, suitable grinding degree, suitable powder content and so on. Then what is appropriate? For example: WBC stipulates that 1 serving of Espresso is 1oz (25~35ml, including Crema), boiled at a temperature of 90.5 to 96 degrees Celsius, brewing pressure 8.5bar~9.5bar, and extraction time of 20 to 30 seconds (no mandatory stipulation). In order to meet the above requirements, a good Italian coffee maker and bean grinder is essential. Often a lot of novice extraction is difficult to concentrate, because at the beginning do not understand, want to get started to play, the result bought a relatively poor so-called 15bar pressure Italian coffee machine and can not accurately adjust the scale of the bean grinder or only suitable for grinding coarse powder single product grinder. I would like to appeal to all novices, do not rush to buy espresso equipment, be sure to do your homework before starting, otherwise it is easy to spend money, but also can not make coffee.

There is also medium fine grinding or very fine grinding (powdered coffee powder) which is finer than fine grinding. The time to grind coffee beans is to grind only the required amount of coffee before brewing coffee. After the coffee bean is ground into powder, its surface area increases and absorbs moisture, which is easy to oxidize. In short, with the passage of time, coffee powder also plays a role of deterioration, resulting in flavor damage.