Method of operating an apparatus for providing a milk-air emulsion, the apparatus at least comprising: a) a milk line through which milk flows, b) at least one air feed system having an adjusting unit for setting an air feed amount for producing a milk-air emulsion from the milk, c) at least one measuring unit for determining at least one physical material property of the milk-air emulsion, and d) a control and evaluation unit, which is designed for setting at least one control variable, e) wherein the device has at least two operating modes, f) wherein in a first operating mode, a milk-air emulsion is dispensed, g) wherein, in the first operating mode, an addition amount of air is introduced into a supplied milk, wherein the control and evaluation unit sets the air addition amount on the basis of a data set which has been determined when passing through a second operating mode, h) wherein in the second operating mode, in the context of a self-adjustment, the data set is created by changing the physical material property by changing the supplied amount of air by means of the adjusting unit, and i) wherein the apparatus, in the first operating mode, enables dispensing of a beverage comprising a milk-air emulsion, wherein step i) is characterized in that, that it includes the following steps: A) presetting a milk-air emulsion based on a manual selection of a beverage; B) executing the first operating mode while enabling a control panel for setpoint adjustment of the amount of air within a setpoint range set in the second operating mode; and C) dispensing of the beverage with the milk-air emulsion. a) a milk line through which milk flows, b) at least one air feed system having an adjusting unit for setting an air feed amount for producing a milk-air emulsion from the milk, c) at least one measuring unit for determining at least one physical material property of the milk-air emulsion, and d) a control and evaluation unit, which is designed for setting at least one control variable, e) wherein the device has at least two operating modes, f) wherein in a first operating mode, a milk-air emulsion is dispensed, g) wherein, in the first operating mode, an addition amount of air is introduced into a supplied milk, wherein the control and evaluation unit sets the air addition amount on the basis of a data set which has been determined when passing through a second operating mode, h) wherein in the second operating mode, in the context of a self-adjustment, the data set is created by changing the physical material property by changing the supplied amount of air by means of the adjusting unit, and i) wherein the apparatus, in the first operating mode, enables dispensing of a beverage comprising a milk-air emulsion, wherein step i) is characterized in that, that it includes the following steps: A) presetting a milk-air emulsion based on a manual selection of a beverage; B) executing the first operating mode while enabling a control panel for setpoint adjustment of the amount of air within a setpoint range set in the second operating mode; and C) dispensing of the beverage with the milk-air emulsion. A) presetting a milk-air emulsion based on a manual selection of a beverage; B) executing the first operating mode while enabling a control panel for setpoint adjustment of the amount of air within a setpoint range set in the second operating mode; and C) dispensing of the beverage with the milk-air emulsion.