The correct Grinding method of Coffee Bean

The degree of grinding should be proportional to the extraction time. The roughness of coffee grinding will directly affect the extraction time and extraction rate. The finer the coffee is ground, the denser the powder layer is, the more coffee powder particles are in contact with hot water, the greater the extraction resistance, the easier it is to prolong the extraction time and improve the extraction rate, and it is easy to over-extract. On the contrary, the coarser the coffee is, the larger the gap in the powder layer is, the less coffee powder particles are in contact with hot water, and the weaker the extraction resistance is, the more difficult it is to prolong the extraction time, and reduce the extraction rate, which is easy to be insufficient. Therefore, the finer the coffee is ground, the longer the extraction time and the higher the extraction rate; the thicker the coffee is, the shorter the extraction time is and lower the extraction rate. Under normal conditions, the fineness of coffee is inversely proportional to the extraction time and extraction rate. The coarser the powder is, the smaller the extraction resistance is, the greater the coffee flow is, the shorter the extraction time is, the lower the extraction rate is, and the lighter the taste is.

Deep roasted beans are thicker and shallow roasted beans are slightly lighter. In addition, before determining the grinding degree of coffee beans, the veteran will first look at the color and oil production of cooked beans. The lighter the roasted coffee is, the more complete and hard the fiber is, the more difficult it is to extract. It is appropriate to pick and grind slightly, but not too fine, so as not to highlight the sharp sour taste. The deeper the roasting degree of coffee, the deeper the damage to the fiber, the easier to extract, it is appropriate to pick a little rough grinding, deep roasting grinding too fine will be bitter. Therefore, the degree of grinding of deep-roasted coffee is generally thicker than that of shallow roasted beans.

Roughness can control bitterness is a good way to control bitterness, because the finer the grinding, the higher the extraction rate, the easier it is to extract high molecular weight astringent bitter substances such as chlorogenic acid, quinic acid, caffeine and carbides. On the contrary, if the grinding is too rough, the lower the extraction rate is, the more difficult it is to extract the astringent bitter substance with high molecular weight, but the sweet taste with middle molecular weight may remain in the coffee grounds because of insufficient extraction, which is a waste. The scale is not immutable. Do not use the same grinding scale for playing coffee. If you know that the density and baking degree of each bean are different, the required scale will not be the same. The scale of very hard beans or shallow roasting can be slightly adjusted to be finer, and the deep roasting can be adjusted thicker. If you think a bean tastes bitter and salty on scale # 3, this is excessive extraction, which can be adjusted to # 3.5 or # 4, which will significantly improve the bad taste spectrum, and vice versa. In addition, the bean grinder should be diligent in maintenance, regularly remove the knife head and remove the oil dirt inside. The knife head is consumable, and it will be dull every 800 to 1000 pounds. Remember to replace it, otherwise the grinding particles will be half-thick and half-thick, which will cause uneven extraction and damage the good flavor of coffee.