A method and apparatus for forming, by means of expansion, plastic preforms into plastic containers in a hollow mold and for filling a substantially liquid product or at least a liquid or solid component of the product into the plastic containers in the hollow mold. The product is filled into the plastic containers while the respective plastic container has inserted therein, at least partially, a stretching rod or a filler neck, and the insertion depth of the stretching rod or of the filler neck is, at the end of the filling process, adjusted such that the volume displaced in the product by the stretching rod or the filler neck corresponds to a predetermined desired ullage.