Science behind the espresso In the following table you can see how much physics goes into a single cup of espresso. You never would have guessed that there is an Istitute Nazionale Espresso Italiano which defines espresso in exact scientific variables:                                                                                                                                                                                                                                                                  espresso-wikipedia Amount of grounded coffee 7g (+/- 0.5g) Water  temperature (leaving unit) 88°C  (+/- 2°C) Temperature of espresso in the cup 67°C (+/- 3°C) Pressure of water 9 bar (+/- 1bar) Time of extraction 25 seconds (+/- 2.5 seconds) Viscosity at 45°C >1.5 mPa s  Total amount of fats > 2mg/ml caffeine <50-60 mg/Tasse Volume of coffee in cup 25ml  (+/-2.5 ml)