Each blend of coffee is the result of the selection of coffee varieties and processing techniques: nevertheless, even if the best raw materials have been chosen and the techniques used are the most sophisticated, for a perfect extraction of the coffee in the cup is important that the machine and the grinder are properly adjusted, and that the bartender uses them correctly.
Ninety degrees Celsius is the reference temperature for the optimal extraction of a good espresso necessary to enhance the organoleptic characteristics of the mixture. This temperature may vary depending on both the mixture used and the degree of roasting of the same, so you can better appreciate all the aromas and flavors. Certain types of products need different temperatures to clearly mark certain characteristics of the individual qualities of coffee that make up the mixture. A high temperature causes the coffee in the cup to be full-bodied but at the same time demarcating the aromatic and acid notes highlighting the strength and the bitterness, on the contrary with a lower temperature these notes are enhanced in order to give the coffee that character that distinguishes it.
The correct operating parameters of the espresso machine, although varying according to the make and model of the machine used, can be summarized as follows:
Boiler pressure: 0.95 bar ± 0.05
Pump pressure: 9 Bar ± 0.5
Temperature: 90 ° C ± 2
Extraction time: 25 sec ± 2
Dose grams: 7 g
Volume in cup: 25 ml ± 2 (in 25 sec.)
Cream height: 2-3 mm