We report here a robust, large-scale synthesis of BaTiO₃ nanopowders using a bioinspired process that first was developed on a much smaller scale. The most advantageous points of this protocol are that it takes place at nearly room temperature (25°C), overcomes many limitations encountered in other scale-up processes (such as the need for external drivers, e.g., heat, radiation or pressure), bypasses the use of surfactants and templates and does not necessitate pH adjustment. The use of a single-source, bimetallic alkoxide with the vapor diffusion of a hydrolytic catalyst (H₂O) provides the necessary conditions for facile crystallization and growth of small, well-defined BaTiO₃ nanoparticles at mild temperatures, yielding batches of up to 250 ± 5 g in a green process. Extension of this method to kilogram-scale production of BaTiO₃ nanocrystals in semicontinuous and continuous processes is feasible.