A method for controlling the formation of foam in a degassing device (10; 10.1, 10.2) for liquids, • wherein the liquid is fed to the degassing device (10; 10.1, 10.2), remains there for the purpose of gas separation and is carried away as a degassed liquid (P') below a free surface formed by the liquid in the degassing device (10; 10.1, 10.2), • wherein the liquid is formed as a liquid film above the free surface and on a surface of a distribution screen and from there enters into the free surface, • wherein the liquid film has the shape of a screen, • wherein a foam forming out of the liquid at a liquid temperature is in each case released above the free surface and therefrom and/or above the liquid film and therefrom, and grows, • wherein the relevant, growing foam, starting at a first heating distance from the free surface releasing the foam and starting at a second heating distance from the liquid film releasing the foam, firstly experiences heating of the liquid temperature to a heating temperature in a register system consisting of a heating (20.1) and a cooling register (20.2), • wherein the relevant, heated foam that grows further then, starting at a first cooling distance from the first heating distance and starting at a second cooling distance from the second heating distance, experiences cooling to a cooling temperature in the register system, • wherein means for carrying out the heat exchange for heating and cooling the foam are permeable to the flow in a direction of growth of the foam (r), • wherein the heating and/or cooling temperature (T1, T2) is/are adjusted depending on the properties of the liquid (P; P') and/or the physical constraints, and • wherein the properties of the liquid are understood to be the volumetric flow rate, viscosity, pressure, temperature and/or composition of the liquid in the region in which said liquid is fed into the degassing device (10; 10.1, 10.2) and the properties of the degassed liquid (P') are understood to be the oxygen concentration (c(O 2)) in the region in which said degassed liquid is carried away out of the degassing device (10; 10.1, 10.2) and the physical constraints are understood to be the pressure and/or the result of the defoaming in the degassing device (10; 10.1, 10.2). • wherein the liquid is fed to the degassing device (10; 10.1, 10.2), remains there for the purpose of gas separation and is carried away as a degassed liquid (P') below a free surface formed by the liquid in the degassing device (10; 10.1, 10.2), • wherein the liquid is formed as a liquid film above the free surface and on a surface of a distribution screen and from there enters into the free surface, • wherein the liquid film has the shape of a screen, • wherein a foam forming out of the liquid at a liquid temperature is in each case released above the free surface and therefrom and/or above the liquid film and therefrom, and grows, • wherein the relevant, growing foam, starting at a first heating distance from the free surface releasing the foam and starting at a second heating distance from the liquid film releasing the foam, firstly experiences heating of the liquid temperature to a heating temperature in a register system consisting of a heating (20.1) and a cooling register (20.2), • wherein the relevant, heated foam that grows further then, starting at a first cooling distance from the first heating distance and starting at a second cooling distance from the second heating distance, experiences cooling to a cooling temperature in the register system, • wherein means for carrying out the heat exchange for heating and cooling the foam are permeable to the flow in a direction of growth of the foam (r), • wherein the heating and/or cooling temperature (T1, T2) is/are adjusted depending on the properties of the liquid (P; P') and/or the physical constraints, and • wherein the properties of the liquid are understood to be the volumetric flow rate, viscosity, pressure, temperature and/or composition of the liquid in the region in which said liquid is fed into the degassing device (10; 10.1, 10.2) and the properties of the degassed liquid (P') are understood to be the oxygen concentration (c(O 2)) in the region in which said degassed liquid is carried away out of the degassing device (10; 10.1, 10.2) and the physical constraints are understood to be the pressure and/or the result of the defoaming in the degassing device (10; 10.1, 10.2).