A method for analyzing the composition of a grain-MOG mixture comprising a kernel fraction and an MOG-fraction. The method includes steps of receiving a grain-MOG mixture, at a thermal excitation location, subjecting a sample volume of the grain-MOG mixture to a thermal excitation using a thermal excitator, generating a thermal image at an imaging location of at least a surface of the sample volume of the grain-MOG mixture that has been subjected to the thermal excitation, processing the thermal image and therewith obtaining data representing the temperature distribution over the thermal image, and relating the temperature distribution to the share of the kernel fraction in the grain-MOG mixture. A device for analyzing the composition of a grain-MOG mixture comprising a kernel fraction and an MOG-fraction is also provided.