Fluorescence spectroscopic and viscosity studies of hydrogen bonding in Chinese Fenjiu.

The associative behavior of ethanol with water and total hydrogen bonding property in Chinese Fenjiu were examined on the basis of fluorescence and viscosity measurements, respectively. Ethyl esters and acetic acid initially strengthened and then weakened ethanol-water hydrogen-bonding structure, while sodium chloride exhibited its enhanced effect. The fluorescence intensities and viscosities were measured for 12 Fenjiu samples of a distillery, aged for 0-20 years in two different types of containers. The ethanol-water fluorescence intensities and viscosities of Fenjiu samples are proportional to their contents of sodium ion and opposite to their contents of total esters. It can be concluded that the strength of the ethanol-water hydrogen bonding as well as the total hydrogen bonding in aged Fenjiu are directly predominated by total esters lost and sodium ion gained in ceramic containers and not dependent on just the aging time.