Optimization of the vaporization of flavour components during wort boiling in the brewery by implementing a rectification column

Changes of wort characteristic components through low thermal stress boiling

This paper systematically studied the changes of wort characteristic components under various low thermal stress boiling, and separation methods of Dimethyl-Sulfide (DMS) accumulated in wort due to low thermal stress boiling. Compared with conventional boiling, the combined boiling (boiling at 3% evaporation rate and 98 °C holding temperature for 30 min) demonstrated that the change rates of solidifiable nitrogen, iso-α-acid and color were no more than 5%, the absorbance of thiobarbituric acid (TBA) reaction mixture decreased by 13.7%, and DMS can be separated by vacuum film stripping after whirlpool. For 98 °C holding temperature boiling, the differences in absorbance of TBA reaction mixture, iso-α-acid and color were 16, 11.6 and 5%, respectively. The solidifiable nitrogen content was equivalent to the 28 mg/L limit and DMS must be removed by vacuum film stripping two times. From the perspective of application, it is necessary to improve the separation efficiency of DMS subsequently.

Separation of Dimethyl Sulfide from Wort by Multi-Layer Centrifugal Film Method

Installing a separation device for undesirable volatile substances represented by dimethyl sulfide (DMS) in wort boiling systems is a common way to reduce the thermal stress and maintain the beer’s flavor stability (characterized by the thiobarbituric acid (TBA) value), but most of these separation devices need to provide additional vacuum or primary thermal energy. This research shows that it can produce self-evaporation that consumes its own sensible heat when wort is in the state of turbulent film. Therefore, a new gas-liquid separation system named the multilayer centrifugal film-forming device (similar to the spinning cone column (SCC)) is proposed, which can strengthen self-evaporation through wort turbulent film and create gas phase conditions for the separation of undesirable volatile substances. The results show that up to 91.6% of the content of DMS in wort could be significantly removed by centrifugal film self-evaporation. The TBA value of wort was reduced by more than 15%, and the wort was not found to be oxidized. Compared with the traditional boiling method, the multi-layer centrifugal film-forming device can significantly save primary energy consumption and reduce energy consumption by 216.4 kJ per liter of wort during the boiling and cooling process.