Tamping – the tamping pressure
Tamping is the often underestimated movement carried out before the portafilter is turned into the brew group – that is the distribution and the tamping pressure of the coffee powder in the portafilter. Only a truly well-trained barista with much experience is perfect at it, because the smooth flow of the movement by which the uniform pressing and, thus, condensing of the coffee powder in the portafilter occurs is decisive; this is the only way to make the water flow uniformly through the portafilter, thereby ensuring optimum extraction and releasing all the desired flavours.
1 | The tamper should be made of metal and not
too light and it should lie comfortably in the hand.
Apart from that, the tamper should always correspond
to the size of the filter, it should have little
play, i.e. distance from the rim.
2 | Before you fill the portafilter, you should regularly
clean it thoroughly using a microfibre cloth.
3 | The portafilter is loosely filled with 7 g coffee
powder per cup.
4 | If necessary, the filled portafilter is tapped
onto the palm of the hand a few times for the coffee
powder to distribute equally.
5 | The portafilter should be placed on a tamping
mat to avoid damage to the outlets. The tamper
station is an alternative solution
The coffee is pressed down vertically
6 | The coffee is pressed down vertically from above with a pressure of approx. 15 kg as uniformly and as accurately as possible – first slightly and then with greater force; the correct position of the hand and the arm is important. To get a feeling for the pressure to be exerted, we recommend to practice using scales. The harder the pressure, the longer will the extraction take. The optimum extraction time is 25 seconds for 25 ml. At the end of the tamping the tamper will be turned in the basket; this gives the coffee powder a smooth finish, the so-called polish.
7 | The water finds the path of least resistance, so that there will be no ideal extraction, if the coffee powder is not pressed down uniformly: Therefore, it is important to shape the coffee powder into a uniform cake through which the water will flow uniformly on the complete surface.