Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
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July/August 2009
The percentage of color derived from the monomeric pigments was greater in the fruit than the wine, while the percentage of color frompolymeric pigment forms showed the opposite trend.
Merlot délestage and control wines showed slight differences in the percentage of color from the different pigment sources. Délestage wines produced over three seasons averaged 4.8% lower color derived from monomeric pigments, 1.4% higher from SPP, and 4.5% higher color from LPP, compared to control wines (Figure II).
Following fermentation, control and délestage-produced Merlot wines did not differ in alcohol percent (v/v), TA, tartaric, malic, and lactic acids, or pH (Table I).
The total tannin concentration was greater in the control wines upon completion of fermentation each year. The total phenol estimations demonstrated a higher concentration in control wines in two of the three years. Total anthocyanins were higher in the control wines in the two years measured, while absorbance at 420 nm + 540 nm, and 420 nm/520 nm, did not demonstrate consistent patterns between délestage and control wines.
Table II provides the concentration of selected phenolic compounds on aged Merlot determined by HPLC analysis. Significant differences among treatments were not observed. Catechin and epicatechin concentrations averaged 37 and 26 mg/L for the control and délestage-produced wines, respectively.
Merlot total glycosides increased by day-two, the first day of fermentation (Table III). By the completion of fermentation (dejuicing), the total glycoside concentration had increased by an average of 388% and 296% for the control and délestage wines, respectively.
Délestage: Step 1
At dejuicing, the total glycoside concentration was greater in the control wines. Phenol-free glycosides increased by day-two. They generally declined by the end of fermentation, andwere in greater concentration in the délestage-produced wines at dejuicing. Results of discrimination sensory analysis suggested that Merlot wines were perceived to differ in aroma and/or flavor in two of three years.
Cabernet Sauvignon
Cabernet Sauvignon must underwent coldmaceration for 48 hours, prior to yeast addition. The effect of fermentation on reducing sugar concentration and percent alcohol (v/v) at various sampling periods was determined by comparing one fermentation vessel each of délestage- and pigeage-produced Cabernet Sauvignon (Figure III).
Délestage: Step 1
Délestage: Step 1