Development of a Monitoring System for Huangjiu Storage based on Electrical Conductivity

In this study, a fast rancidification detection method was developed for Huangjiu in pottery jars based on the principle of electrical conductivity changes caused by microbial contamination. The change of total acid in Huangjiu was positively correlated with the increase of electrical conductivity. This method was applied to an online monitoring system for Huangjiu storage in stainless steel tanks. When the electrical conductivity exceeds the normal fluctuation range (Mean + 3 standard deviations) of previous data, the monitoring system recognizes the microbial contamination. By optimizing the conductivity-temperature compensation coefficient and conductivity statistical method, the standard deviation of the method was reduced and the sensitivity of microbial pollution monitoring was improved. The ranges of conductivity and compensation coefficient of common types of Huangjiu were estimated. Interference in conductivity measurements due to environmental factors was minimised through the synchronous comparison of conductivity data for multiple tanks of Huangjiu. The standard deviation (SD), which indicates the fluctuation range of the system, decreased from 143 μS/cm to 2 μS/cm. The monitoring system was then applied in Huangjiu storage tanks with capacities of 60 t and 300 t. Through the comparison of conductivity data change, the abnormal signals caused by microbial contamination during the storage of Huangjiu were found in time. Meanwhile, through off-line detection of total acid of Huangjiu, the effectiveness of microbial contamination on-line detection was verified.