AbstractEnsuring good ignition properties over long periods of time necessitates maintaining a good level of flow porosity in powders of initiator materials and preventing particle coarsening. To simulate flow porosity changes of such powder materials over long periods of time a common strategy is to perform accelerated aging experiments over shorter time spans at elevated temperatures. In this paper, we examine historical accelerated‐aging data on powders of pentaerythritol tetranitrate, an important energetic material, and make predictions for long‐term aging under ambient conditions. We develop an evaporation–condensation‐based model to provide some mechanistic understanding of the coarsening process.