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.