The invention relates to a method for introducing a vaporous heat carrier into a liquid product, in particular a food product or beverage, and in this case in particular viscous products, for example desserts, sauces or concentrates, in which method the vaporous heat carrier heats the liquid product in order to form a germ-free product, and also to an injector for carrying out the method. The object of the present invention is to provide a method of the generic type and an injector for carrying out said method, with which method and injector, in particular, a reduction in the heat transfer capacity of the injector is prevented over the entire production time. In the context of the method, this is achieved in that three physical measurement variables which can be detected during operation of the injector are used as indicators of the formation of product deposits, at least one of said three physical measurement variables being detected, and in that, depending on one or more of these physical measurement variables, an automatically controlled axial movement of the displacement body is carried out in such a way that the heat transfer capacity from the vaporous heat carrier (D) into the liquid product (P) remains the same.
