The knowledge course of Italian Coffee-the effect of cloth Powder on extraction

In the extraction of espresso, the same extraction parameters are sometimes found to be unstable, and espresso liquid gushes out of control.

The unstable flow rate is likely to be caused by the "channel effect". In general, water is inert and will choose a path with less resistance.

When the density of the coffee powder layer is uneven, the water will break through to the parts with relatively low density, and the water will flow away quickly from the cracks, resulting in insufficient extraction.

The causes of the channel: uneven dose distribution, filling on the inclined plane, tapping on the pressed handle, blocking or poor quality of the filter basket used.

Cloth powder: uneven distribution of powder is easy to produce channel effect.

Degree of grinding: affects the speed at which water passes through the powder layer

Powder amount: affect the thickness of the powder layer and change the speed at which the water passes through the powder layer. Too thick the powder layer leads to the time process of the water passing through the powder layer. The upper layer is extracted too much and the lower layer is extracted less.

The extraction is not uniform; the powder layer is too thin and passes through the powder layer too fast, resulting in insufficient extraction

Powder pressing strength: in a certain range, the greater the powder pressing strength, the slower the flow rate.

(note: when making espresso, you need to ensure the consistency of each process)