SEBASTIAN KAPPLER (1), Martin Krottenthaler (1), Thomas Becker (1)
(1) Technische Universität München-Weihenstephan, Lehrstuhl für Brau- und Getränketechnologie, Freising, Germany
Hop is an essential ingredient for beer. Iso-α-acids are the main
contributor of bitterness in it. Unfortunately, the utilization rate up
to finished beer amounts only to about 30% of the α-acids dosed to the
wort before and during boiling. Several technologies to increase hop
utilization were suggested within the past few years. Nevertheless,
often a negative impact to beer quality was reported. Also, essential
oils present in hops can play an important role in beer flavor. Aroma
impressions like fruity, flowery, and citrusy mostly are based on those
hop compounds. Unfortunately, because of evaporation the transfer rate
is usually quite low. Depending on time and intensity of wort boiling,
in the majority of cases only traces of those compounds can be found in
finished beer. To raise the amount of aroma-active hop oils, various
technologies are used. Usually, a late hop dosage at the end of boiling
or a dosage directly into the whirlpool is done. Another possibility is a
dosage to the beer during storage. All of these techniques create a
unique hop aroma. Although already in the beginning of the 20th century a
dosage of hops to the first wort during lautering to increase
bitterness and hop aroma was mentioned, nearly no knowledge exists about
the influence of that early hopping on hop aroma and bitterness. In
this paper, the influence of variations in the early-hopping technology
on utilization rates and beer quality is presented. It was shown that a
dosage of hops at that early stage of wort preparation can lead to a
very unique hop aroma and also bitterness perception can vary.
Pilot-scale trials were done to evaluate the influence of a first wort
hopping technology on sensorial and analytical attributes. Particular
attention is directed towards the aroma and bitterness perception of
fresh and forced aged beers. The results presented in this paper provide
a better understanding of the conversions during the brewing process
and its influence on beer quality. Suitable approaches toward an
improved yield of bitter acids and an improved bitter quality as well as
aging stability are shown.
Sebastian Kappler received a Dipl.-Ing. degree in brewing and
beverage technology from Technische Universitaet Muenchen in 2008. He
began his employment with the Augustiner-Wagner brewery in Munich,
Germany, as an apprentice to a brewer and maltster in 2000. After
achieving the level of assistant, he started his studies on brewing
science at the Technische Universitaet Muenchen. Since 2008 he has been
working as a scientific employee at the Chair for Brewing and Beverage
Technology in Weihenstephan. The topic for his doctoral thesis is the
evaluation of the factors affecting the yield of isohumulones during
preparation of wort.
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