Process engineering parameters for the deaIcoholisation of beer by means of falling film evaporation and its influence on beer quality

Today the production of "alcohol-free" and alcohol-reduced beers is based mainly on the removal of alcohol after fermentation. Besides the diffusion of alcohol through suitable membranes, evaporation under vacuum has widely established itself on the market. Falling film evaporation seems to be the most advantageous evaporation technique available, since it combines simple plant construction with a high efficiency. Over the past years, several membrane systems for beer dealcoholisation have been installed, assumingly following a not always objectively founded trend to avoid any thermal stress on beer. Although membrane systems deliver quite satisfactory results in the majority of cases, this does not at all indicate that membrane-based alcohol removal was fundamentally superior to evaporation methods, or that it would in principle yield alcohol-free and alcohol-reduced beers of higher quality. There are indeed studies on the influence of falling film evaporation on the quality of "alcohol-free" and alcohol-reduced beers, but a comparison of the impact of various process engineering parameters has not been published until now. This paper systematically covers the advantages and disadvantages of different working methods in alcohol removal from beer by falling film evaporation.