Sensory Session
Andreas Brandl, Doemens Academy GmbH, Stefanusstr. 8, 82166 Gräfelfing, Germany
Co-author(s): Christina Schönberger, Joh. Barth und Sohn, Nürnberg,
Germany; Urs Wellhoener, Boston Beer Company, Breinigsville, PA, USA
ABSTRACT: Beer flavor is very complex, being derived from
components that arise from a number of sources. In bottom fermented
beers the sulfur-containing components from yeast metabolism, such as
hydrogen sulfide and sulfur dioxide, make a significant contribution to
beer flavor, whereas in top fermented beers often the fruity and estery
substances are dominant. Especially in freshly filled beers hydrogen
sulfide can exceed the very low flavor threshold (5 µg/L) leading to an
unpleasant off-flavor. During beer storage sulfur flavor will be
degraded due to oxidative processes. Thus the sulfury notes need to be
controlled in fresh beers and especially in dry-hopped beers, as the
fruity hop aroma interferes with the sulfury components, which leads to
an unbalanced sensory impression. An easy and pragmatic way to control
hydrogen sulfide is by adding a special activated carbon as a filtering
aid during filtration or lagering. Tests with non–dry-hopped beers with
the addition of activated carbon showed a significant reduction in
hydrogen sulfide leading to improved acceptance in sensory evaluation.
In a pilot scale (5 hL) we adopted a commercial dry-hopped beer recipe
and filter dry-hopped bottom fermented beers with and without activated
carbon to determine the flavor impact on the final product. The beers
were controlled by sensory evaluation, and the hydrogen sulfide level
was measured, as well as the concentration of hop aroma substances. The
aim was to emphasize the characteristic hop derived spicy and fruity
notes coming from the dry-hopping resulting in a more balanced beer even
in fresh conditions.
Andreas Brandl studied brewing and
beverage technology at TU Munich-Weihenstephan. From 2001 to 2005 he
worked on his Ph.D. thesis on the implementation of PCR-based methods in
brewery quality assurance. In 2005 he began employment as a project
engineer for aseptic filling lines at Krones AG, and in 2007 he changed
to the Bitburg Brewery Group as head of the brewery pilot plant. In
Bitburg he was responsible for the organization and documentation of
brewing technology trials. Since 2010 he has been working for the
Doemens Academy as head of the microbiology lab and consultant in
brewing technology.
VIEW PRESENTATION 202
