Abstract:

No legal detection wavelength has been published in the current national standard involving the measurement of beer turbidity. Different measurement results for the same beer samples are always given. This not only brings trouble to beer manufacturers, but also makes it difficult to ensure beer quality. In the present study, a quick method for directly determining the turbidity of bottle contained beer without opening was presented. Turbidity was measured with Haffmans VOS Rota 90/25  type double-filter beer turbidity analyzer at both 90°and 25°, and the measurements results were compared with those obtained by the conventional method. There was no significant difference between both methods at the same wavelengths (P＞0.05) and different results, however, were obtained at different wavelengths. The use of red filter could only eliminate the intervention from brown color of bottles, but made the determination of green bottles inaccurate. When green filter or no filter was used, the results of determining different size bottles were not significantly different. As a conclusion, the presented analytical method is valid. Nevertheless, the selection of detection wavelength influences determination accuracy.

Key words: beer, turbidity, quick determination, turbidity determination of bottle contained beer without pouring out