Barista knowledge the concept and principle of Coffee Grinding

The operation of crushing roasted coffee beans is called grinding.

The ideal time to grind coffee is to grind it before cooking. Because ground coffee is easy to oxidize and lose its flavor, especially without proper storage, coffee powder is also easy to change flavor, so it is naturally impossible to cook mellow coffee.

Some people are afraid of trouble or do not want to buy a bean grinder, so they usually buy ready-made coffee powder when drinking coffee at home. At this time, they should pay special attention to the problem of storage. After the coffee powder is opened, it is best not to place it at room temperature at will. A more appropriate way is to put it in a sealed jar and refrigerate it in the refrigerator, and do not put it together with garlic, fish and shrimp and other foods with heavy flavor. Because the coffee powder is easy to absorb, a careless coffee becomes a strange taste coffee, then even the best quality coffee will be spoiled. However, some people put the cooked coffee powder in the refrigerator as a deodorant, which is a good way to make the best use of things.

When grinding beans, the size of the powder depends on the way it is cooked. Generally speaking, the shorter the cooking time, the finer the ground powder; the longer the cooking time, the thicker the ground powder. Grinding coffee powder with 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 over-extraction, the coffee may be very bitter and lose its aroma. On the other hand, if the powder is coarse and cooked too fast, resulting in insufficient extraction, the coffee will be tasteless because it is too late to dissolve the water-soluble substance in the powder.

No matter what kind of grinder is used, it is bound to generate heat by friction in operation. Most of the fine substances are highly volatile, the heat of grinding will increase the speed of volatilization, and mellow is lost in the air.

After the coffee bean is ground, the cell wall will completely disintegrate, the area of contact with air will increase a lot, the rate of oxidation and deterioration will become faster, and the coffee will lose its flavor within 30 seconds to 2 minutes. Therefore, it is recommended not to buy coffee powder, it is best to buy coffee beans, grinding before drinking, grinding should be brewed as soon as possible.