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.
