A system for determining a solubility of a substance comprises a holder to hold a sample comprising an amount of the substance and an amount of the solvent system. The system further comprises a temperature conditioner to alter a temperature of the sample, an optical measurement device to measure an optical parameter of the sample and a control device to control at least the temperature conditioner and the optical measurement device. The control device may be programmed to alter the temperature of the sample by the temperature conditioner, measure the optical parameter of the sample by the optical measurement device, and determine the solubility of the substance from a change of the optical parameter of the sample as a function of the temperature.