Sensory Session
Caroline Scholtes, Université catholique de Louvain, Earth and Life Institute (ELIM), Louvain-la-Neuve,Belgium
Co-author(s): Etienne Bodart, Florence Peeters, Laurent Melotte, and
Sonia Collin, Université Catholique de Louvain, Earth and Life Institute
(ELIM), Louvain-la-Neuve, Belgium
ABSTRACT: The evolution of short chain fatty acids,
esters, and fusel alcohols was investigated using various aging
procedures. In unrefermented beers, a 5 day treatment at 40°C or 3 days
at 60°C led to an evolution similar to what 1 year at 20°C would have
induced. These assays also were representative of two refermented beers
in which the yeast was in particularly good shape, as shown by the
relative stability of its esters. Yet, for global sensorial analyses,
both accelerated aging procedures were unable to mimic other defects,
like Madeira and phenolic off-flavors. In refermented beers where yeast
was autolyzed (decrease in fruity esters), accelerated aging strongly
overestimated the C5, C6, C8, and C10 carboxylic acids, as well as
beta-phenylethanol. In that case, released yeast glucosidases were
suspected to hydrolyze glucosyl esters and glycosides available in the
medium. When Brettanomyces strains were present in the bottle,
heat also strongly promoted the levels of isovaleric, hexanoic, and
octanoic acids. In these Belgian-style beers, accelerated aging could
help to assess the physiological state of yeast in the bottle.
Graduating
in 2007 as a bio-engineer from Catholic University of Louvain
(Belgium), Caroline Scholtes completed her education in 2008 with a
master’s degree in brewing science. In 2010, she started a Ph.D. program
at the same university. Her research focuses on aging of Belgian
special beers with regard to raw materials, brewing process, and storage
conditions and correlates this to modification of organoleptic profile,
especially Madeira off-flavor and volatile phenols. She is also a
teaching assistant in beer chemistry at the same university.
VIEW PRESENTATION 201
