Crystal polymorphism poses a severe problem for the pharmaceutical industry as it can induce significant changes in the physico-chemical characteristics of the material. This can render a medicine toxic (increased chemical decomposition) or inefficient (lowered solubility). In order to elucidate the factors leading to polymorphism, we propose to continue our investigation into the model substance metha-hydroxybenzoic acid. It is bimorphic with the crystal forms crystallising from different solvents (methanol and acetonitrile). Recent results show that the less stable polymorph can be stabilised by water content of the mother liquor. We would like to measure the compound in methanol solutions (crystallisation of stable polymorph) with two different water concentrations. Measurement on SANDALS will enable us to model the liquid structure and investigate the solute interactions with water.