Alcoholic fermentation fluids are containing various sugars, ethanol and carbon dioxide in aqueous solution. Precondition for the concentration determination with ultrasound based methods is a calibration model describing the dependency of typical ultrasound parameters like the sound velocity from the concentration of the dissolved components and the temperature. For this reason, the sound velocity c in aqueous solutions with CO2, CO2+saccharose, CO2+ethanol and CO2+saccharose+ethanol in dependence of the temperature in a range of 2°C up to 30°C and constant CO2-pressures of 2.01∙105Pa and 3.01∙105Pa was measured and compared with the data in equivalent solutions without a carbon dioxide fraction. Carbon dioxide induces, like the components saccharose and ethanol, an increase Δc of the sound velocity. The density ρ of the investigated fluids was calculated by the interpolation of literature data combined with several approximation approaches. The adiabatic compressibility κ, which can be determined from the relationship κ=1/(c2∙ρ), is decreased by all investigated solutes, showing a linear dependency from their mole fractions χ. Different values ∂κ/∂χ can be explained by the molecular structure of the investigated molecules. It could be shown, that the overall decrease ΔκSa+Et+CO2 of the compressibility induced by saccharose, ethanol and CO2 can be depicted as a sum ΔκSa+ΔκEt+ΔκCO2 of contributions generated in solutions containing only one of the three components. Regression functions ΔcSa+Et+CO2(χSa, χEt, χCO2, T), ΔκSa+Et+CO2(χSa, χEt, χCO2, T) have been calculated for the change of the sound velocity and compressibility respectively.     «

Alcoholic fermentation fluids are containing various sugars, ethanol and carbon dioxide in aqueous solution. Precondition for the concentration determination with ultrasound based methods is a calibration model describing the dependency of typical ultrasound parameters like the sound velocity from the concentration of the dissolved components and the temperature. For this reason, the sound velocity c in aqueous solutions with CO2, CO2+saccharose, CO2+ethanol and CO2+saccharose+ethanol in depende...     »