37. Process engineering opportunities and impact of relevant parameters in alcohol-free beer production with a focus on thermal dealcoholization

Magdalena Mueller (1); (1) Technische Universität München, Freising, Germany

Technical Session 11: Engineering and Packaging
Monday, August 15  •  9:45–11:30 a.m.
Plaza Building, Concourse Level, Governor’s Square 15

Alcohol-free beer as an isotonic beverage with reduced alcohol and calorie content is considered to be an innovative product with high growth potential in the brewing industry. The aim of this project, which is in line with the current industrial goals, is to produce alcohol-free beers with a taste similar to conventional alcoholic beers and a comparable positive culinary value. In addition to limited fermentation, thermal dealcoholization is an established industrial process in life science technology. The problem with the product resulting from limited fermentation is that it is often reminiscent of unfermented wort. This is because the typical aroma compounds relevant to a balanced aroma and taste can’t be produced due to the limited yeast metabolism. The products obtained by the thermal process are often described as unbalanced, sour and have a less fruity bouquet. The difficulty in the thermal process is that important aroma components evaporate throughout dealcoholization because the separation of the ethanol is not absolutely selective. Consequentially many volatile aroma compounds, such as higher alcohols, formed during fermentation are vaporized with the ethanol. The sensory descriptions of the products in this segment vary substantially. The reason for this variation may be due to the lack of a tool specifically designed to evaluate the peculiarities of the product, for example the ratio between sweetness and sourness. To address this problem a descriptive sensory scheme was developed that was adapted to top- and bottom-fermented beer types. With this sensory scheme a comprehensive and detailed evaluation of alcohol-free beers is possible. This includes a characterization of typical flavors (e.g., hoppy, malty fruity) and off-flavors (e.g., roasty, bready), according to the aroma classes of Meilgaard, as well as the features typical of alcohol-free beers, such as harmony of sweetness/sourness, etc. Using this sensory scheme, a discussion of the process optimizations that can be achieved during thermal dealcoholization in regard to the aroma concentrations will be presented. The process parameters that will be discussed are backflow, evaporation temperature and aroma recovery. Furthermore, the possibilities available to a brewery in terms of improving, intensifying and modifying the taste of alcohol-free beers before and after the actual process are shown. Examples of this are the modifications to the basic beer, such as degree of fermentation, fermentation process, and subsequent steps such as dry-hopping and blending. The collected data reveals the influence of the processing parameters on the quality of alcohol-free beers. Through parameter setting it was possible to improve the quality of alcohol-free beers.

Magdalena Müller studied life science technology at the Technische Universität München, Center of Life Science Weihenstephan, Germany. After several internships in the food industry during her studies, working with dairy and pharmaceutical products, she graduated in 2012 with her diploma degree in food process engineering. Since 2013 she has been working with Prof. T. Becker and Dr. Tippmann at the Institute of Brewing and Beverage Technology, Technische Universität München. Her Ph.D. work is on the sensory optimization of alcohol-free beer gained by thermal dealcoholization. The focus is on sensory evaluation and process engineering investigations to describe the impact of various process parameters.