Three operating parameters of hydrodistillation have been optimised by a response surface method using a central composite design to obtain high yields of essential oil from a rhizome of the Zingiberaceae species Zingiber cassumunar (Z. cassumunar). The optimal conditions for the maximum essential oil produced (6.64 g) were found to be an extraction time of 4 hr, a solid-to-solvent ratio of 3:150 and a hydrodistillation rate of 78 ml/hr. The study was subsequently continued with the three proposed models of the extraction process. Kinetics models proposed by Milojevi et al. and Hervas et al. were suitable for the process under low (20 ml/hr) and high distillation rates (70 ml/hr), whereas the model by Ana et al. was valid for all ranges of rates studied (20–70 ml/hr). It can be concluded that the hydrodistillation rate was one of the important parameters for determining the extraction kinetics.