A vane rheometer was used to measure the modulus of foam systems. Modulus development in a reactive polyurethane foam system was captured using a commercial stress-controlled rheometer with a four-blade vane geometry test fixture. The results were compared to those from a temperature programmed flooded parallel plate method. The vane geometry method was shown to be a convenient and accurate way to measure the physical gelation time of the reactive foaming system, without the complexity of the temperature-program method. Shaving cream was used as a calibration material to show the validity of the vane method for foam modulus measurements. For open cell foams, the error in the vane method increases due to the additional compressibility of the foam. The nature and magnitude of this error was analyzed via numerical simulation.