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Figure I. Effect of cold soak, fermentation,
and post-fermentation on total phenols of
control (cap punched) and délestage produced
Merlot wines in season 3; n = 3.
was described. Evaluation
was done based on olfactory (aroma) and
retronasal aroma andmouthfeel (referred
to as flavor). Evaluations of aroma and
flavor occurred at different times.
Descriptive analysis was performed
nine months post-fermentation on
non-pooled Cabernet Sauvignon wine
treatment replicates, using 11 trained
panelists as described byM.Meilgaard
et al.17 Panel members evaluated three
replications of the two products
(pigeage and délestage) six times.
Panelists had one to 10 years experience
in descriptive or consensus sensory
analysis. A list of descriptors was
developed from three pre-evaluation
training sessions with standards used
for training prepared as reported by B.
Zoecklein et al.43
Statistical analysis Results
Merlot
The Merlot fruit averaged 21.5° Brix,
3.7 pH and 5.62 TA for the three years,
typical of the region. Berries averaged
1.18 g, with 2.4 seeds, for the three seasons
of this study. In years 2 and 3,
Merlot fruit monomeric pigments were
responsible for an average of 70.5%, SPP
19.7%, and LPP 9.8% of the total color.
By the end of délestage-treated fermentations,
an average 25% of seeds
had been removed each year. Fermentation
rates were similar among treatments.
Total phenols, estimated by the
absorbance at 280 nm, increased linearly
from crush until dejuicing for
both délestage and control wines
(Figure I). At day-six (dryness), control
lots had a total phenol concentration
slightly greater (7.7%) than the
délestage (typical of this study).
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CABERNET SAUVIGNON fruit (18,144
kg) grown in northern Virginia was
hand-harvested at 23° Brix, and immediately
destemmed, crushed, sulfur dioxide
(30 mg/L) added, fermentable nitrogen
levels were measured and adjusted,
and itwas divided into treatment lots (as
described above). Musts were given a
cold maceration (cold soak) period of 48
hours at 10°C prior to fermentation, and
yeasted (as described above).
Treatments consisted of 1) control,
fermentation using a 10,000-Lmechanical
pigeage, or 2) délestage, conducted
in similar size and shape conventional
stainless steel fermentation tanks (fill
height to diameter ratio, 1:1).
Pigeage consisted of punching three
times daily, 10 minutes per punch, with
punching consisting of cycles of one
minute down and 30 seconds up.
Délestage was conducted daily as
described above with the following
exception: liquid was drained onto a flat
tray (0.75 x 1.2m)with a screen (2.39mm
diameter holes). Fermentationswere conducted
at an average liquid temperature
of 27°C(range 26° to 33°C) and an average
cap temperature of 30°C (range 28° to
34°C). Mechanical punching and
délestagewere conducted for seven days.
Pressing was performed post-dryness
(2.0 g/L reducing sugar), 22 days following
the beginning of fermentation,with a
5,000-L tank press, by allowing free
drainage for one hour, followed by pressing
to one bar. Free-run and press-run
wines were not combined.
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Chemical analysis
General fruit,must, and wine chemistries
were conducted as described by
B. Zoecklein et al.43
HPLC analysis was conducted 18
months post-fermentation on selected
phenols in finished agedwines described
by Price et al.19
Total tannins (catechin equivalents),
and the percentage of color from
monomeric pigments, small polymeric
pigments, and large polymeric pigments
was estimated using the procedures
of Adams and Harbertson,1 and
Harbertson et al.11 The concentration of
total glycosides was estimated by the
analysis of glycosyl-glucose in thawed
samples as described by P. J. Williams
et al.,41 and modified by R. S. Whiton
and B.W. Zoecklein.40 Analysis of phenol-
free glycosides was conducted as
described by B. Zoecklein et al.44
Sensory analysis
Discrimination testing was performed
on pooled wine replicates of
Merlot and Cabernet Sauvignon, using
triangle difference comparison described
by M. Meilgaard et al.17 The wines were
evaluated six to eight months post-fermentation
in the Virginia Tech wine sensory
laboratory, under controlled conditions
that included red lighting to help
eliminate color bias.
Panel membership required regular
wine consumption (at least one glass per
week) and attendance at two informational
sessionswhere themethodology of
evaluation
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