A highly controllable thermal distillation reactor system (25) and method (30) allow volatile compounds to be efficiently removed from the plant matter without use of solvents, and can separate compounds with different vapor pressure characteristics. The system has a Thermal Distillation Reactor (TDR) (13) into which the plant material is charged. The TDR provides for high rates of heat transfer coupled with small thermal diffusion length scales to allow substantially all of the plant material to be within a narrow temperature range, which enhances the separation purity cuts. The system provides high removal efficiencies whilst minimizing any impurities resulting from pyrolysis or thermal destruction to the cellulose, hemi-cellulose or lignin within the plant material.