3. How to check quality of coffee grinder (Coffee grinder knowledge summary)
Mis à jour : 28 nov. 2019
The advantages and disadvantages of the coffee grinder are mainly reflected in the following aspects:
After grinding the coffee beans into coffee powder, each coffee powder can be regarded as a separate individual, and each coffee powder will be extracted when contact with the water. The longer time the coffee powder extraction takes if coffee powder is big, the shorter time the coffee extraction takes if the coffee powder is small.
The size of the coffee powder is what we call the fineness of the coffee powder.
The better quality of the coffee grinder is, the more similar shape of coffee powder fineness is. And the shape is almost the same if excellent coffee grinder. This will ensure that the same progress of extraction of each coffee powder throughout the extraction process.
The coffee powders milled in different coffee cutter have different shapes, and the extraction method and taste will also change. Coffee powder may be flat, granular, etc.
The standard for espresso coffee powder is that the fine coffee powder visible to the eye with a diameter of 0.3 mm or less is. If applied to a Hand-brewed coffee, it can be a diameter of 0.1 mm or less. These fine powders can block the gap between normal coffee powders and even block the filter paper or filter bowl. The perfect condition after coffee grinding is that each coffee powder is almost the same size.
But in fact it is inevitable that these very fine powders will be produced in the grinding process, similar to the slag that fell off when we break the biscuits. The extraction rate of this very fine powder will be much faster than other powders, which means that when other coffee powders are completely extracted, these fine powders must be over-extracted.
The fine powder in hand brewing process also clogs the filter paper causing a decrease in flow rate and an extended extraction time that leading to over-extraction.
Therefore, the less too fine coffee powder produced by the coffee grinder in the grinding, the better the coffee grinder is.
Many people will find that the coffee powder will agglomerate during the use of the coffee grinder. The main reason is the effect of static electricity.
Excessive motor speed produces heat and the wear of the cutter, even the humidity of the environment, can cause agglomeration.
But the most troublesome thing is static electricity. Once the grinding is too fine, the effect of static electricity on the coffee powder will appear. Therefore, the formation of agglomerates causes the imbalance of filling of coffee powder, which ultimately affects the quality of the coffee powder.
The coffee powder ground by the coffee bean grinder will reach the powder storage bin through a passage and then dial a paddle or directly through the passage to the powder bowl.
However, some of the coffee powder remains in the storage bin and the passage. These coffee powders are exposed to the air for a long time and naturally lose a lot of flavor. So they are not fresh enough, and will enter the next cup of coffee with the next coffee powder outlet.
In order to reduce the effect of residual powder on coffee, a certain amount of coffee powder is discarded in advance. So the old coffee powder in the channel and the powder storage bin is replaced. Then it's time to grind the new coffee powder.
However, the amount of waste will naturally increase. so the shorter the channel of the coffee grinder, the better the coffee grinder is.