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.
