While the fermentation rates were
generally similar between treatments,
some differences in the wines were
noted. There were no differences in
alcohol percent (v/v), TA, pH, or tartaric,
malic, or lactic acids, between
pigeage and délestage-produced wines
(Table IV).
Total tannin, total phenols, and total
anthocyanins were greater in pigeageproduced
wines. Differences in
absorbance at 420 nm + 520 nm, and
420 nm/520 nm, were noted between
délestage and pigeage. Table II provides
the concentration of selected
phenol compounds on aged Cabernet
Sauvignon. Significant differences
among treatments were not observed.
Tannin concentrations remained stable
until active fermentation, then increased
and were higher in pigeage-produced
wines at most
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sample periods (Figure IV).
Total phenols (AU280) increased for both
treatments during pre-fermentation maceration,
and significantly during fermentation
(Figure V).
At dejuicing, the total phenol concentration
in the press wines averaged
14.5% and 9.8% higher than free run
for délestage and pigeage wines,
respectively (data not shown). At the
completion of fermentation, free-run
pigeage-produced wines had higher
absorbance at 420 nm + 520 nm, and
lower 420 nm/520 nmabsorbance than
délestage wine (Table IV).
During the cold soak period, the percentage
of color from monomeric anthocyanins
declined dramatically in the juice,
then declined or remained constant for the
first threedays of fermentation(FigureVI).
By sampling on day-10 (completion
of alcoholic fermentation), the
percentage of
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monomeric pigments
had declined for both treatments.
At dejuicing, day-22, the percentage
of color from monomeric pigments
in the pigeage free-run wine
averaged 33% higher than the
délestage wine.
Press wines showed a similar trend
(data not shown). The percentage of color
fromsmall polymeric pigments increased
during the cold soak period, remained or
declined during the first five days of fermentation
for both treatments, then
increased slightly (Figure VII).
The percentage of color from large
polymeric pigments increased during
cold soak and fermentation for both
pigeage and délestage treatments, and
was slightly higher in the délestage
wines at dejuicing (Figure VIII).
Post-fermentation, free-run Cabernet
Sauvignon délestage and pigeage
wines demonstrated 34.6% compared
to 43.5% color from monomeric pigments,
53.8% compared to 49.6% color
from SPP, and 11.6% compared to 6.9%
color from LPP (Table IV), respectively.
Following cold soak, total glycoside
concentration was greater in the pigeage
than délestage tanks by an average of 49%
(Table V). Total glycosides increased during
fermentation (cold soak to day-10) for
both treatments. By the completion of fermentation
(day-10) and at dejuicing, total
glycoside concentrations were similar in
pigeage and délestage wines. Phenol-free
glycosides were in higher concentrations
in pigeage wines post-cold soak and at
dejuicing.
Discrimination sensory analysis of
Cabernet Sauvignon délestage- and
pigeage-produced wines indicated differences
in aroma and flavor. The principal
component analysis (PCA) for
aroma indicated variation among
treatment replicates that accounted for
59% of the variance (Figure IX). The
first and second principal component
analysis of flavor accounted for 63% of
the variance (Figure X).
Discussion
A relatively high concentration of
extractable seed tannins has been shown
to negatively impact wine quality in
Virginia and other wine-producing
regions. The study was conducted using
1,416 kg lots, and seed removal in conjunction
with délestage, to help improve
red wine mouth feel.
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Figure IV. Effect of pigeage and délestage
on Cabernet Sauvignon - tannin concentration
during cold soak, fermentation, and
post-fermentation; n = 3.
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Figure V. Effect of pigeage and délestage on
Cabernet Sauvignon - total phenols during
cold soak, fermentation, and post-fermentation;
n = 3.
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