The metal binder jetting (MBJ) process is a powder bed-based Additive Manufacturing (AM) process, which is attracting growing interest. In this process, a liquid binder deposited by a print head bonds the powder particles to create green parts. For a reliable metal binder jetting process, the metal powder must have high quality. The morphology and particle size distribution have a major influence on the flowability and sinterability of the material. In this work, the aging process is observed particularly with regard to the slightly disappearing fine fraction during the process. A practical method is presented to reliably detect the ageing process of the powder. In addition, a method is developed to stop or curb ageing to support constant printing conditions. The experiments are conducted using 17-4PH stainless steel. Several properties of powders and parts are analysed such as particle size distribution, green part density, powder bed density and dimensional tolerances.