Title: Hopping Technology in Relation to alpha-Acids Isomerization Yield, Final Utilization, and Stability of Beer Bitterness
Authors: Jaskula, Barbara ×
Goiris, Koen
Van Opstaele, Fillip
De Rouck, Gert
Aerts, Guido
De Cooman, Luc #
Issue Date: 2009
Publisher: American Society of Brewing Chemists
Series Title: Journal of the American Society of Brewing Chemists vol:67 issue:1 pages:44-57
Abstract: A detailed study of a-acids isomerization kinetics was undertaken by performing pilot-scale brewing experiments with T90 hop pellets, nonisomerized hop extract, and nonisomerized hop extract plus hop residue. In addition, a brew was prepared by adding preisomerized hop extract at the onset of wort boiling. Compared with the use of nonisomerized hop extract, significantly higher isomerization yields were obtained when vegetative material was included in the hopping. However, when vegetative material was present final alpha-acids utilization was compromised by large losses of iso-alpha-acids postboiling. Evidence of reverse isomerization of iso-alpha-acids during wort boiling was not found when preisomerized hop extract was applied. The results obtained using quantitative HPLC profiling confirmed that both alpha-acids and iso-alpha-acids were not stable upon beer aging. In particular, trans-iso-alpha-acids underwent rapid degradation in finished beer. Therefore, beers prepared with preisomerized hop extract containing relatively less-sensitive traps-isomers, and thus more cis-isomers, show improved bitterness stability upon aging compared with conventionally hopped beers.
ISSN: 0361-0470
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Biology, Campus Kulak Kortrijk
Technologiecluster Bioengineering Technologie
Bioengineering Technology TC, Technology Campuses Ghent and Aalst
× corresponding author
# (joint) last author

Files in This Item:

There are no files associated with this item.

Request a copy


All items in Lirias are protected by copyright, with all rights reserved.

© Web of science