This work highlights the effect of the stirring, the temperature and the supersaturation on the cooling crystallization of L-Glutamic acid (LGIu) polymorphs. First, solubility measurements of the metastable polymorph alpha and the stable polymorph beta were performed. Then, crystallization experiments were carried out in stirred vessel and in stagnant cell. All these experiments were monitored by in situ devices. The effect of the temperature on the LGIu polymorphs was found to be more relevant than the supersaturation in the stirred crystallizer. In the stagnant cell, only the stable form beta crystallized regardless of the operating conditions. Moreover, an unexpected and new habit of the beta form was discovered and confirmed. These results suggest that the temperature and the stirring can strongly affect the nucleation and the growth kinetics of polymorphic forms. (C) 2015 Elsevier B.V. All rights reserved.