The importance of bean grinder to ESP

When cooking, large powder particles and small powder particles will produce different taste (because the surface area of powder particles is different).

Assuming that there are only "one size" powder particles in the powder bowl (of course, this is actually impossible), the coffee brewed by  will have a combined flavor (e.g. sweetness 1.2 + aroma 2.3 + chocolate 0.9), and the overall taste may be clearer and cleaner (a bit like the sound of describing hi-fi). On the contrary, if there are 20, 30, or even 100 kinds of powder particles in the powder bowl, the coffee brewed by  will have 20, 30, or even 100 combinations of flavor, and the overall taste may be relatively thick and cloudy.

Changing the roughness means changing the size of coffee particles. And the so-called average refers to the degree to which coffee particles vary in size? To the lowest.

I also believe that the shape of particles is also important, but the understanding in this respect may be more complicated. Coffee beans are the nuclei in the fruits of coffee plants and contain many plant cells. Plant cells (plant cell) have cell walls (cell wall). After roasting (roasting), more water in the coffee beans is drained, so that the coffee beans are squeezed and broken during under burr grinders, forming coffee powder particles. These coffee powder particles are different in shape and volume. A good bean grinder makes these differences in shape and volume? To the lowest.

Ultra-fine powder will have a negative effect on coffee and make the taste cloudy. However, in the grinding process, the production of ultra-fine powder is inevitable.

Powder shape-the closer the ball / wave shape is, the more stable the area-to-volume ratio is, the more stable the powder is arranged in the brown cake and even the cake resistance, the easier the cooking quality is, the more irregular the shape is (e.g flake, easy to produce by the low-level propeller machine), the greater the variation of the powder arrangement in the brown cake, the more unstable and turbid the powder is.

Ultra-fine powder-except that ultra-fine powder itself is easy to over-extract, the presence of ultra-fine powder (even a small amount) will greatly increase cake resistance (imagine a coarse water pipe but pour into sand, causing blockage), resulting in overall over-extraction, and uneven distribution of ultra-fine powder will cause dead point and channel effect, leading to cooking instability and turbidity.