Different concentrates from sheep's milk cheese whey, with up to 26·5% solids, were prepared in the laboratory by reverse osmosis, and their viscosities and heat capacities determined over the temperature range 5–80 °C. These products behaved like other liquid milk concentrates previously studied, so that similar analytical expressions could be used to predict these physical properties in cheese whey as a function of the temperature and solid content. A nomogram is also given for an easier computation of each property. The water in liquid dairy products and their concentrates up to 40% solid content appears to behave as pure, free water with respect to its partial contribution to the heat capacity of these products, its apparent heat capacity being 4·208±0·016 kJ. kg-1 °C-1.