Barista training knowledge the concept and principle of Coffee Grinding

The grinding of roasted coffee beans is called grinding.

The ideal time to grind coffee is before it is cooked. Because ground coffee is easy to oxidize and lose flavor, especially in the absence of proper storage, coffee powder is also easy to change flavor, naturally unable to cook a fragrant coffee.

Some people are afraid of trouble or do not want to buy a bean grinder, usually at home to buy coffee has been ground ready-made coffee powder, then pay special attention to the storage problem, coffee powder after opening is best not placed at room temperature, more appropriate way is placed in a sealed jar into the refrigerator, and do not and garlic, fish and shrimp and other heavy taste of food together. Because coffee powder is easy to absorb flavor, a careless coffee becomes a strange taste, so even the best quality coffee is ruined. Some people put ground coffee in the refrigerator as deodorant, which is a good way to make the best use of it.

When grinding the beans, the thickness of the powder depends on how it is cooked. Generally speaking, the shorter the cooking time, the finer the ground powder; the longer the cooking time, the coarser the ground powder. Grinding coffee powder of appropriate thickness is very important for making a good cup of coffee, because the extraction of water-soluble substances in coffee powder has its ideal time, if the powder is very fine, and cooked for a long time, resulting in excessive extraction, coffee may be very bitter and lose aroma; on the other hand, if the powder is very coarse and cooked too fast, resulting in insufficient extraction, then coffee will be tasteless, because there is no time to dissolve the water-soluble substances in the powder.

No matter what kind of grinding machine is used, it will certainly generate heat by friction during operation. Most of the fine substances are highly volatile, and the heat of grinding will increase the speed of volatilization, and the aromatic alcohol will be lost in the air.

After coffee beans are ground, the cell wall will completely disintegrate, the area in contact with air will increase a lot, the oxidation and deterioration speed will become faster, and coffee will lose flavor within 30 seconds to 2 minutes. Therefore, it is recommended not to buy coffee powder, it is best to buy coffee beans, grind before drinking, grind well should be brewed quickly.