Method for checking plausibility of a gas mixture volumetric flow rate in a burner in which a gas mixture comprising a gas and a fuel gas is burned by a combustion process in a combustion chamber, wherein the combustion process is monitored by evaluation of a measured value V, from at least one sensor, wherein the measured value V is related to the combustion process in such a way that the quality of the combustion of the fuel gas is detectable, wherein the method comprises the following method steps: a. imposing a pulse-like modulation on a volumetric flow rate of the fuel gas, in particular a volumetric flow rate change G on a volumetric flow rate of the fuel gas, at a first point in time t start in accordance with a time series G(t); b. measuring the measured value V starting from a second point in time t 2 and capturing a measured value time series V(t); c. calculating in each case a product P of the first value from the measured value time series V(t) at a point in time t i and each value of the time series G(t) and subsequently forming a sum S i of all the calculated products; d. storing the first sum S i in a buffer memory; e. calculating in each case a product P of the second value from the measured value time series V(t) at a point in time t i+1 and each value of the time series G(t) and subsequently forming a sum S i+1 of all the calculated products; f. storing the first sum S i+1 in a buffer memory; g. repeating the two steps e. and f. for the points in time t i+n until a predefined point in time t stop; h. selecting the maximum S max of the stored sums S i to S i+n and ascertaining the point in time t i+x with respect to the sum S max; i. determining the time difference between t start and t i+x as a delay time t lauf of the pulse-like modulation through the volumetric flow rate of the gas mixture to the combustion chamber; j. comparing the delay time t lauf with a target value t soll for a theoretical volumetric flow rate from a memory and deducing the given volumetric flow rate. a. imposing a pulse-like modulation on a volumetric flow rate of the fuel gas, in particular a volumetric flow rate change G on a volumetric flow rate of the fuel gas, at a first point in time t start in accordance with a time series G(t); b. measuring the measured value V starting from a second point in time t 2 and capturing a measured value time series V(t); c. calculating in each case a product P of the first value from the measured value time series V(t) at a point in time t i and each value of the time series G(t) and subsequently forming a sum S i of all the calculated products; d. storing the first sum S i in a buffer memory; e. calculating in each case a product P of the second value from the measured value time series V(t) at a point in time t i+1 and each value of the time series G(t) and subsequently forming a sum S i+1 of all the calculated products; f. storing the first sum S i+1 in a buffer memory; g. repeating the two steps e. and f. for the points in time t i+n until a predefined point in time t stop; h. selecting the maximum S max of the stored sums S i to S i+n and ascertaining the point in time t i+x with respect to the sum S max; i. determining the time difference between t start and t i+x as a delay time t lauf of the pulse-like modulation through the volumetric flow rate of the gas mixture to the combustion chamber; j. comparing the delay time t lauf with a target value t soll for a theoretical volumetric flow rate from a memory and deducing the given volumetric flow rate.