Abstract: The invention relates to compositions comprising an ester of a polyol and a mixture of fatty acids, wherein at least a part (I) the esterified fatty acids has a chain length of 5-12 carbon atoms and another part (II) of the esterified fatty acids has a chain length of 16-22 carbon atoms, and wherein the composition has a viscosity of 7000 mm2/s or less, when tested according to ASTM (D2531). Such compositions have unexpected good low temperature properties, in particular a good rheology after having been kept for a prolonged time at a low temperature (e.g. at −30° C.). These compositions are suitable for use as (part of) hydraulic fluid in applications at low temperatures.