Device for characterising at least one liquid material, comprising: - characterisation means, A liquid melt of said liquid material, - rotating means for mechanically stirring (4, 5) said liquid melt of said at least one liquid material, the mechanical stirring means (4, 5) comprising: - a central part, extending along a longitudinal axis, intended to be positioned above the liquid melt of said at least one liquid material, comprising an inner cavity forming an analysis chamber delimited by a wall of the central part, 10 the central part comprising a first end connected to the characterisation means, and - a plurality of mechanical stirring blades, connected to a second end of the central part, opposite to the first end of the central part, the second end of the central part extending over a height (h) along the longitudinal axis of the central part and being hollow so as to ensure fluidic communication between the inner cavity and the liquid melt of said at least one liquid material, the characterisation means being configured to enable the analysis of the surface of said at least one liquid material, situated in the portion directly in line with the inner cavity of the central part, 20 characterised in that the mechanical stirring blades are totally immersed in the liquid melt of said at least one liquid material, in that the central part comprises one or more orifices formed in a traversal manner in its wall delimiting the inner cavity and situated above the second end of the central part bearing the mechanical stirring blades when the device is in place in the liquid melt of said at least one liquid material, orifices being partially immersed according to a height in the liquid melt of said at least one liquid material, and in that each mechanical stirring blade comprises at least one stirring wing (8a, 8b) oriented according to a non-zero angle of orientation (a) with respect to a transversal axis perpendicular to the longitudinal axis of the central part. - characterisation means, A liquid melt of said liquid material, - rotating means for mechanically stirring (4, 5) said liquid melt of said at least one liquid material, the mechanical stirring means (4, 5) comprising: - a central part, extending along a longitudinal axis, intended to be positioned above the liquid melt of said at least one liquid material, comprising an inner cavity forming an analysis chamber delimited by a wall of the central part, 10 the central part comprising a first end connected to the characterisation means, and - a plurality of mechanical stirring blades, connected to a second end of the central part, opposite to the first end of the central part, the second end of the central part extending over a height (h) along the longitudinal axis of the central part and being hollow so as to ensure fluidic communication between the inner cavity and the liquid melt of said at least one liquid material, the characterisation means being configured to enable the analysis of the surface of said at least one liquid material, situated in the portion directly in line with the inner cavity of the central part, 20 characterised in that the mechanical stirring blades are totally immersed in the liquid melt of said at least one liquid material, in that the central part comprises one or more orifices formed in a traversal manner in its wall delimiting the inner cavity and situated above the second end of the central part bearing the mechanical stirring blades when the device is in place in the liquid melt of said at least one liquid material, orifices being partially immersed according to a height in the liquid melt of said at least one liquid material, and in that each mechanical stirring blade comprises at least one stirring wing (8a, 8b) oriented according to a non-zero angle of orientation (a) with respect to a transversal axis perpendicular to the longitudinal axis of the central part. - a central part, extending along a longitudinal axis, intended to be positioned above the liquid melt of said at least one liquid material, comprising an inner cavity forming an analysis chamber delimited by a wall of the central part, 10 the central part comprising a first end connected to the characterisation means, and - a plurality of mechanical stirring blades, connected to a second end of the central part, opposite to the first end of the central part, the second end of the central part extending over a height (h) along the longitudinal axis of the central part and being hollow so as to ensure fluidic communication between the inner cavity and the liquid melt of said at least one liquid material, the characterisation means being configured to enable the analysis of the surface of said at least one liquid material, situated in the portion directly in line with the inner cavity of the central part, 20 characterised in that the mechanical stirring blades are totally immersed in the liquid melt of said at least one liquid material, in that the central part comprises one or more orifices formed in a traversal manner in its wall delimiting the inner cavity and situated above the second end of the central part bearing the mechanical stirring blades when the device is in place in the liquid melt of said at least one liquid material, orifices being partially immersed according to a height in the liquid melt of said at least one liquid material, and in that each mechanical stirring blade comprises at least one stirring wing (8a, 8b) oriented according to a non-zero angle of orientation (a) with respect to a transversal axis perpendicular to the longitudinal axis of the central part.