Abstract:
The
quality
of
red
wine
is
primarily
determined
by
the
flavor,
aroma,
and
color.
A
common
wine
making
technique
used
to
improve
these
characteristics
is
the
pre-‐fermentation maceration. In this study two pre-fermentation maceration
techniques were used, one was a traditional cold soak and the second involved
addition of dry ice to the grapes. Samples were taken daily and yeast viable cells were
assessed by growth on WL media. This also enabled the major species of yeast to be
identified. The two major yeast species seen throughout the pre-fermentation
maceration were Pichia membranaefaciens and Kloeckera apiculata. Yeast
population in both pre-fermentation macerations increased during the maceration
period. However, after three days the population in the cold soak treatment was 1 log
or greater than the yeast population in the dry ice treatment. This difference remained
for the rest of the maceration. After wines were produced their color and phenolic
contents were analyzed. Total color, polymeric pigments and monomeric
anthocyanins in wines that underwent a pre-ferementation maceration were not
significantly different than the control. However, there was a significant difference in
the amount of tannins between the dry ice and cold soak treatment to the control.
