Improvement on the oxidative beer flavor stability using active packaging material—Advantages or disadvantages in comparison to SO2-addition

Packaging (Bottles, Draft, Cans) Session
Victoria Schiwek, Technische Universität Berlin, Department of Biotechnology, Chair of Brewing Sciences, Berlin, Germany
Co-author(s): Thomas Kunz, Constanze Ruff, and Frank-Jürgen Methner, Technische Universität Berlin, Department of Biotechnology, Chair of Brewing Sciences, Berlin, Germany

ABSTRACT: The beer off-flavor caused by oxidation has been attributed to the formation of specific aging compounds (e.g., aldehydes), through several reaction mechanisms. Although the mechanisms differ in their reactive components, they all involve species formed from molecular oxygen, highlighting the importance of avoiding oxygen entry in the brewing process and the final beer by using suitable packaging material. The aim of this study was to figure out the influence of SO2 addition as an antioxidant before filling in comparison to the use of different crown liner materials with O2 scavenger properties and the effect of a combination of both on oxidative flavor stability. Recent studies have illustrated that the application of EPR spectroscopy in combination with the determination of specific aging compounds by GC-MS, such as 3-/2-methyl butanal as an oxygen indicator, SO2 determination, and sensory analysis are useful tools to demonstrate the influencing factors on consumption of natural antioxidants and oxidative flavor stability over the course of shelf life. The described technique combination is predetermined for the evaluation of SO2 addition in the brewing process or active packaging materials and their impact on oxidative beer stability. For the investigation it was necessary to use the same beer matrix and the same filling station with different crown caps to get an objective comparison with significant results. A part of the beer was separated in a different tank to add 6 mg of SO2/L before filling at the same filling station. As expected, the beer with SO2 addition and oxygen scavenger in the crown cap exhibited higher flavor stability (as measured by all measurement techniques) during storage in comparison to the non-scavenger controls or without SO2 addition. But, the influence on oxidative beer stability of each O2 scavenger material was very different. A remarkable and, for the reaction mechanism, important point is the comparable increase in oxidative stability with SO2 addition or O2 scavenger. It also leads to a different positive effect on the formation of specific aging compounds during storage. In summary, the highest oxidative stability was observed with the best crown liner and SO2 addition. On the other hand the best O2 scavenger was able to compensate for more than 6 mg of SO2 addition per liter during storage so the beer had a higher oxidative stability after 4 months of storage, suggesting it acts directly after filling and during storage. The worst but cheapest O2 scavenger showed an effect only after longer storage through the inhibition of oxygen diffusion through the crown cap. All together this research work offers brewers useful knowledge about the best procedure for increasing oxidative beer stability through SO2 addition and/or active packaging material.

Victoria Schiwek studied pharmaceutical and chemical engineering at the Beuth University of Applied Sciences from 2002 to 2007. The topic of her diploma thesis was “Optimized Analytical Methods for the Determination of SO2 in Beer and Malt.” Since 2010 she has been working as vice head of laboratory for the Chair of Brewing Science at TU Berlin.