An apparatus and method of processing grain by raising the moisture content of the grain relative to a target level. As the grain is moved through a processing area, the moisture content and the mass flow of the grain are measured. Each measurement is converted to an electronic signal and the signals are fed to a programmable controller which blends the two signals and produces a single output control signal that is fed to a proportional control valve. The control valve acts responsive to the control signal to adjust the amount of moisture added to the grain at a wetting station. An additive such as a surfactant can be metered into the water supply.