A method for monitoring the rate of rise of a filling material, in particular, fresh concrete, in a vertically fillable formwork with at least one optical sensor device and a computing device comprising at least the following steps: a) providing at least one limit value for the rate of rise of the feed material in the at least one computing device, wherein at least one limit value is based on at least one parameter of the ambient conditions, in particular the air temperature, a reference temperature and/or an installation temperature; b) providing at least one measurement interval for an optical measurement with the optical sensor device in the at least one computing device, wherein, in particular, the at least one measurement interval is dependent on consistency information of the filling material; c) filling the formwork with the filling material; d) carrying out optical measurements with the optical sensor device on at least one current fill layer height of the filling material in the formwork during the filling of the formwork with the filling material; e) calculating the current rate of rise (v B) of the filling material when filling the formwork with the filling material at least by means of the measured values of the optical measurements of at least one current fill layer height, at least one parameter of the ambient conditions, and at least one time measurement (t) in the at least one measuring interval in the at least one computing device, wherein a time stamp is set in the at least one computing device for this purpose or a time measurement device is used to determine the timing; f) outputting at least one warning signal if the at least one current rate of rise (v B) of the feed material reaches the at least one provided limit value of the rate of rise of the feed material. a) providing at least one limit value for the rate of rise of the feed material in the at least one computing device, wherein at least one limit value is based on at least one parameter of the ambient conditions, in particular the air temperature, a reference temperature and/or an installation temperature; b) providing at least one measurement interval for an optical measurement with the optical sensor device in the at least one computing device, wherein, in particular, the at least one measurement interval is dependent on consistency information of the filling material; c) filling the formwork with the filling material; d) carrying out optical measurements with the optical sensor device on at least one current fill layer height of the filling material in the formwork during the filling of the formwork with the filling material; e) calculating the current rate of rise (v B) of the filling material when filling the formwork with the filling material at least by means of the measured values of the optical measurements of at least one current fill layer height, at least one parameter of the ambient conditions, and at least one time measurement (t) in the at least one measuring interval in the at least one computing device, wherein a time stamp is set in the at least one computing device for this purpose or a time measurement device is used to determine the timing; f) outputting at least one warning signal if the at least one current rate of rise (v B) of the feed material reaches the at least one provided limit value of the rate of rise of the feed material.