Coarse ground coffee is suitable for filtering coffee pot (traditional American brewing machine), medium ground coffee is suitable for filtering, flannel filtering and siphon coffee pot brewing methods, and fine ground coffee is most suitable for coffee distiller (also known as drip coffee machine). And remind you that the shorter the brewing time, the finer the ground particles will be. Because the smaller the particles, the larger the contact area with hot water, so the brewing time is shorter. And grinding too fine will make coffee bitter, and it is easier to block the coffee machine; Grinding too coarse will produce less tasteless coffee.