C. NEUGRODDA (1), M. Gastl (1), T. Becker (1); (1) Lehrstuhl für Brau- und Getränketechnologie, Freising, Germany
Quality
Wednesday, June 4 - 1:00 p.m.-2:45 p.m.
Level 3, Crystal Room
Beer foam is one of the most important beer quality parameters; it is
one of the primary characteristics by which consumers judge beer
quality. It is generally accepted that beer components, such as
polyphenols, hop bitter substances, or proteins, have an impact on beer
foam stability. In this study we compare three widely used MEBAK foam
analysis methods (Ross and Clark, Steinfurth foam stability tester, and
NIBEM) and determine the influence of beer components on foam stability.
Overall over 40 beers were analyzed with standard MEBAK beer analysis,
foam stability methods, among others, and the results were correlated
with each other. It is well known that proteins are the “backbone” of
beer foam. Therefore we analyzed the beer protein profiles by means of
microfluidic capillary electrophoresis and determined the impact of
different protein fractions on foam. Our results show that the foam
analysis methods are comparable with each other and have high
reproducibility. An interesting fact is that the foam analysis methods
react differently with the different beer components or protein
fractions. Some protein fractions have a negative correlation with the
results obtained by Steinfurth and NIBEM, but have a positive
correlation with the results of Ross and Clark., whereas another
fraction correlated positively with all foam analyses used. In summary
the protein analyses showed that several protein fractions have a strong
influence on foam stability. Further we found that the results of the
standard MEBAK analysis used are not suitable for prediction of beer
foam stability. Although the influence of beta-glucan is controversial
in the literature, its content showed a positive influence on the
results of all foam measuring methods tested.
Christoph Neugrodda was born in Trier, Germany. After completing his
military service in 2003, he began an apprenticeship as a brewer and
maltster at the Bitburger brewery in Bitburg, Germany, finishing in 2006
as the best of the examination. Until beginning his studies, he worked
as a brewer at the Bitburger brewery. He studied brewing and beverage
technology at the Technische Universität München-Weihenstephan, Germany,
in 2006. He graduated as an engineer with a Dipl.-Ing. degree in 2012
and delivered his diploma thesis on the proteins of hops. Since 2012 he
has been working as a scientific employee at the Institute for Brewing
and Beverage Technology in Weihenstephan. His research focus is the
influence of texture and molecular composition of foam on the flavor
release from beer. Aside from work, Christoph is interested in hunting
and running, as well as watching and participating in sports and music.
