A calibration method, said method comprising the steps of: providing a beverage dispensing system, said beverage dispensing system comprising a pressure chamber having a removable lid and defining a first inner volume, said pressure chamber being fluidly connected to a pressurization system, said pressurization system being capable of supplying a specific volume of gas per operating cycle of said pressurization system to said first inner volume of said pressure chamber, said pressure chamber further having a pressure sensor for sensing the pressure of said first inner volume of said pressure chamber, providing a collapsible beverage container, said collapsible beverage container including a second inner volume of beverage, said second inner volume being smaller than said first inner volume, said beverage preferably being a carbonated beverage such as beer, soft drink or wine, opening said lid, introducing said beverage container into said first inner volume of said pressure chamber and closing said lid, increasing said pressure value from a predetermined low pressure value to a predetermined high pressure value by using said pressurization system, determining the number of operating cycles defining the sum of operating cycles of said pressurization system used for raising said pressure value from said predetermined low pressure value to said predetermined high pressure value, and establishing a measure of said specific volume of gas per operating cycle of said pressurization system of the beverage dispensing system by using said predetermined low pressure value, said predetermined high pressure value, said first inner volume, said second inner volume and said number of operating cycles. providing a beverage dispensing system, said beverage dispensing system comprising a pressure chamber having a removable lid and defining a first inner volume, said pressure chamber being fluidly connected to a pressurization system, said pressurization system being capable of supplying a specific volume of gas per operating cycle of said pressurization system to said first inner volume of said pressure chamber, said pressure chamber further having a pressure sensor for sensing the pressure of said first inner volume of said pressure chamber, providing a collapsible beverage container, said collapsible beverage container including a second inner volume of beverage, said second inner volume being smaller than said first inner volume, said beverage preferably being a carbonated beverage such as beer, soft drink or wine, opening said lid, introducing said beverage container into said first inner volume of said pressure chamber and closing said lid, increasing said pressure value from a predetermined low pressure value to a predetermined high pressure value by using said pressurization system, determining the number of operating cycles defining the sum of operating cycles of said pressurization system used for raising said pressure value from said predetermined low pressure value to said predetermined high pressure value, and establishing a measure of said specific volume of gas per operating cycle of said pressurization system of the beverage dispensing system by using said predetermined low pressure value, said predetermined high pressure value, said first inner volume, said second inner volume and said number of operating cycles.