How do you make espresso? What is the channel effect? How would you like your espresso?

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Coffee cake cracks affect the taste

To make a good espresso, the first thing to guard against (channeling): if there are cracks in the coffee cake, according to the inertia of water, it will flow away from the place with the lowest resistance. Therefore, the coffee powder on both sides of the crack will be overextracted after a certain period of time, but other parts of the cake pressed powder may not be wet through at all and become underextracted. Therefore, although 14 grams of coffee powder to make 21 grams of "standard coffee", if there are cracks in the cake, in fact, the extraction may be less than half. What is more, the part of the crack that tastes bad becomes bitter due to excessive extraction. Therefore, the goal of opening the handle with the naked eye is to "let it taste what should be tasted, and stop when it is enough, regardless of whether it reaches the standard or not."

If espresso is an acid (A) bitter (B) balanced drink, then the ristretto with shorter extraction time is mainly acid (A), because the fruit acid has high water solubility and will be extracted first. On the contrary, excessive extraction is characterized by a taste similar to peanut ash (C). The ideal espresso is only A B, but in fact, a small amount of C is inevitable. Ristretto can be processed with the same coarse but short time to avoid the emergence of B; another method is to extract the coarser powder with a longer time. Even if it's only 20 milliliters, we call it espresso profile. Is there an A, a C and a large cup? That is the ristretto that failed to extract.

It is more interesting to follow the sense of taste than to blindly conform to standards.