With time-domain reflectometry (TDR) the dielectric permittivity of foodstuffs can be measured with the use of a cheap cable tester which has proved its value in soil science. The materials which are examined are solutions of mono; di- and polysaccharides. The influence of the species, the composition and the temperature on the dielectric permittivity is considered. TDR is a suitable method for determining the water content of a sample, because the dielectric permittivity is mainly influenced by this property. Temperature has a complex influence on the measured dielectric permittivity: at high water contents the relation is negative, while at low water contents this relation is positive. This results in a cross-over point at water contents of about 55%. The dependency of the dielectric permittivity on water content is also modeled with a mixing model for non-interactive dispersed media. From this model it can be concluded that, in the frequency range used, the interactive carbohydrate solutions behave more and more as noninteractive media at lower temperatures.