A method of operating a sealing station of a packaging machine for producing, in the case of possibly varying filling degrees , packages (V) with at least substantially similar package appearances, the method comprising the following steps: • filling (A) a free package volume (P) enclosed between a lower and an upper packaging material and defined by at least one package (V) positioned within the sealing station with a gas (G), intended to be used for creating a desired atmosphere, from an initial pressure (P1) prevailing in the package volume (P) up to a predetermined gas flushing pressure (P2), • detecting (B), at least temporarily during filling (A) of the package volume (P), a pressure curve by means of at least one pressure-detecting sensor system connected to the package volume (P), the pressure curve being preferably detected on the basis of a time-dependent pressure curve (K IST ) between the initial pressure (P1) and the predetermined gas flushing pressure (P2), • comparing (C) the detected pressure curve with a reference pressure curve detected preferably on the basis of a pressure curve (K REF ), which, in turn, is time-dependent, for filling a known free reference package volume (P REF ) of at least one, in particular empty reference package (V REF ) positioned within the sealing station with the gas (G) between the initial pressure (P1) and the predetermined gas flushing pressure (P2), • calculating (D) a filling degree of the package (V) positioned within the sealing station on the basis of the comparison between the detected pressure curve and the reference pressure curve , and/or a volume flow (V) on the basis of the comparison (C) of the detected pressure curve with the reference pressure curve , and • setting (E) at least one process parameter (PP) at the packaging machine with due regard to the calculated filling degree and/or volume flow (V). • filling (A) a free package volume (P) enclosed between a lower and an upper packaging material and defined by at least one package (V) positioned within the sealing station with a gas (G), intended to be used for creating a desired atmosphere, from an initial pressure (P1) prevailing in the package volume (P) up to a predetermined gas flushing pressure (P2), • detecting (B), at least temporarily during filling (A) of the package volume (P), a pressure curve by means of at least one pressure-detecting sensor system connected to the package volume (P), the pressure curve being preferably detected on the basis of a time-dependent pressure curve (K IST ) between the initial pressure (P1) and the predetermined gas flushing pressure (P2), • comparing (C) the detected pressure curve with a reference pressure curve detected preferably on the basis of a pressure curve (K REF ), which, in turn, is time-dependent, for filling a known free reference package volume (P REF ) of at least one, in particular empty reference package (V REF ) positioned within the sealing station with the gas (G) between the initial pressure (P1) and the predetermined gas flushing pressure (P2), • calculating (D) a filling degree of the package (V) positioned within the sealing station on the basis of the comparison between the detected pressure curve and the reference pressure curve , and/or a volume flow (V) on the basis of the comparison (C) of the detected pressure curve with the reference pressure curve , and • setting (E) at least one process parameter (PP) at the packaging machine with due regard to the calculated filling degree and/or volume flow (V). <EOS>