Recent simulation research has proved the principle that it is possible to exercise closed-loop control over the particle shape of the crystals produced from cooling crystallisation processes through tracking an optimum temperature or supersaturation profile which can be obtained through optimisation using a morphological population balance (M-PB) model. Here, attention is given to experimentally designing a closed-loop control system on a real crystallisation process to produce the desired shape for rodlike crystals. An optimization algorithm was applied to an M-PB model developed for L-glutamic acid crystallisation to find the optimal profiles of cooling temperature and supersaturation that lead to the desired shape of beta-form rod-like product crystals. A closed-loop feedback control system was designed to control the solution temperature or concentration to track the optimum trajectory. On a 1-I crystalliser, It was demonstrated that crystals of different shape can be obtained using the developed closed-loop control methodology. Both supersaturation control and temperature control are compared with each other, and also with constant supersaturation strategy in performance in achieving the final product shape. (C) 2011 Elsevier Ltd. All rights reserved.