Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
email: Office@practicalwinery.com
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July/August 2009
WINEMAKING
Figure VII. Effect of pigeage and délestage on Cabernet Sauvignon - small polymeric pigments (SPP) as a percentage of total color during cold soak, fermentation, and post-fermentation; n = 3.
Figure VIII. Effect of pigeage and délestage on Cabernet Sauvignon - large polymeric pigments (LPP) as a percentage of total color during cold soak, fermentation, and post-fermentation; n = 3.
Figure IX. Projection of aroma attributes on principal components 1 and 2 for Cabernet Sauvignon pigeage- and délestage-produced wines; n=11.
The higher percentage of color from monomeric pigments in pigeage wines at the end of fermentation may reflect increased fruit extraction. Cabernet Sauvignon color from SPP increased during cold soak, and appeared to increase only slightly from the beginning of fermentation to dejuicing (average 7.8%). The percentage of color from LPP increased during fermentation by approximately 150%.
The Cabernet Sauvignon LPP-to-SPP ratio, as percent of color, ranged from0.11 during cold soak to 0.37 at dejuicing. The SPP would be expected to contain pigment dimers and trimers formed by acetaldehyde crosslinking of anthocyanin and flavan-3-ols.28 The LPP fraction likely contains anthocyanins that have reacted directly with polymeric flavan-3-ols, or by acetaldehyde crosslinks, to formpolymeric pigments large enough to precipitatewith BSAin the assay.
Figure X. Projection of flavor attributes on principal components 1 and 2 for Cabernet Sauvignon pigeage- and délestage-produced wines; n=11.
Phenol-free glycosides were in larger concentration in Merlot, but not Cabernet Sauvignon, délestage-produced wines. The analysis of phenolfree glycosides includes all but shikimic acid metabolites. This analysismay be a better approximation of the glycosidically-derived aroma/flavor pool than is the total glycosides assay.
Discrimination sensory analysis on pooled treatment replications indicated differences in aroma and flavor among Merlot andCabernet Sauvignondélestage and control wines. PCA analysis of Cabernet Sauvignon treatment replications demonstrated differences between délestage and pigeage wines, and among replications of the same treatment.
It is evident that délestage wine-1 and pigeage wine-3 have similar aroma and flavor profiles. While treatments were dejuiced each day at the same Brix, individual replicate variation occurred, possibly as a result of the degree of seed removal, pomace drain time, and/or oxygen exposure.With the exception of replicate- 1, délestage wines were characterized by pungent black pepper aromas and pungent raspberry flavors.
Conclusion
An important industry goal is to be able to customize maceration methods, predicated on fruit composition and desired outcome. This study evaluated the impact of a cap management technique in conjunction with seed removal.
Given the large variability in fruit composition, the response to a particular maceration technique may be variable. Délestage with partial seed removal appeared to slightly modify the percentage of color derived from monomeric and large polymeric pigments. The result of discriminatory sensory analysis generally suggested differences in aroma and flavor between délestage and control wines.
These differences were charted for the Cabernet Sauvignon, and were variable among replications. These differences may or may not justify the additional effort involved in the utilization of délestage with seed removal as a cap management strategy.