Automatic Control of Solvent Density in Grand Canonical Ensemble Monte Carlo Simulations We present automated methods for determining the value of Adams' B parameter corresponding to a target solvent density in grand-canonical ensemble Monte Carlo simulations. The method found to be best employs a proportional-integral control equation commonly used in industrial process control applications. We show here that simulations employing this method rapidly converge to the desired target density. We further show that this method is robust over a wide range of system sizes. This advance reduces the overall CPU time and user effort in determining the equilibrium excess chemical potential in these systems.