A coffee blend is the result of a selection of raw coffee and the most elaborated with production techniques. Nevertheless, in order to ensure a perfect coffee it is essential that the espresso coffee machine and the coffee grinder are correctly regulated and that they are used correctly by the barista.
Even if the brand and model of the machine vary,
the correct set-up parameters of the espresso machines can be seen as follows:
Boiler Pressure: 0,95 bar ± 0,05
Pump Pressure: 9 Bar ± 0,5
Temperature: 90°C ± 2
Extraction time: 25 sec ± 2
Amount in grams: 7 g
Volume in cup: 25 ml ± 2(in 25 sec)
Cream height: 2-3 mm
Two clarifications regarding pressure:
-
Boiler pressure: can vary between 0.9 and 1.1 bar. Between 0.9 and 1.0 for machines that
distribute relatively little coffee as they are not in frequent use. Between 1.0 and 1.1 for
machines used frequently (more than 50 cups of coffee every hour) and that use water
from the boiler for cappuccinos and tea. The boiler pressure is directly proportionate to the
temperature reached.
-
Pump pressure: during coffee extraction the manometer indicator must be in the green
zone, between 8 and 10 bar (correct pressure 9 bar). When the pump pressure increases the
distribution speed will increase and the coffee extraction will decrease.