A method of manufacturing and optimizing energetic propellant grains includes generating an optimal surface area to mass fraction burned ratio profile for a predetermined solid structure including propellant grains; using the profile as a target function of a topological optimization process to generate a 3D form of a propellant grain; developing a negative of the 3D form of the propellant grain; mixing and densifying the negative with an energetic material in an uncured form in a mixer to create a structure including the energetic material and embedded negative; and solvating the negative from the structure, wherein the negative comprises a 3D propellant grain. The developing of the negative of the 3D form of the propellant grain may occur using a predetermined material in an additive manufacturing process. The negative may be soluble in the predetermined material, and the energetic material may be insoluble in the predetermined material.