When optimizing the process of grapes juice manufacture not just to obtain an excellent quality, but also to develop a data base is essential to know the evolution of physical properties, such as viscosity or heat capacity elevation. These properties are affected by temperature and dry matter content. The aim of this study was to establish a mathematical relation between these variables. In order to assess and select a suitable mathematical model the known data were fitted in different equations. Tests results have shown that at constant dry matter content the temperature and the viscosity are related by an exponential equation while between temperature and heat capacity variation a “heat capacity” model seems to be the most appropriate.