Marais, J. (2003). Effect of Different Wine-Making Techniques on the Composition and Quality of Pinotage Wine. I. Low-Temperature Skin Contact Prior to Fermentation. S. Afr. J Enol. Vitic., 24(2), 70-75.
The effect of low-temperature skin contact prior to fermentation in the production of Pinotage wines was studied over four vintages.
The fruit was harvested from the same block and split into seven lots. The control was fermented immediately and the pre soak samples were held at either 10 or 15°C for 1, 2 or 4 days prior to fermentation.
All wines are fermented in a 25° temperature controlled room.
Post fermentation no malolactic fermentation or oak treatment.
The wines were analysed for total flavonoids, total tannins and total anthocyanins.
In the bottled wine there was a slight increase in total phenolics in the wine given the 4 days at 10° C. treatment and 2 days at 15° C. treatment over the others. Wines with extended contact may contain lower anthocyanin concentration due to degradation or precipitation of these compounds.
Wines were analysed for iso-butyl acetate, iso-amyl acetate, hexyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate and ethyl decanoate.
Pinotage wines are characterised by relatively high ester concentrations. Ester concentrations declined with increased soak times.
The wines are analysed at six months of age for berry/plum intensity and overall wine quality.
The 4 days at 10° C. treatment provided the highest quality wines and the control and 4 days at 15° C. treatment the lowest.
Increasing the temperature from 10 to 15OC appeared detrimental to quality.
Similar results have been found in trials carried out with Pinot Noir.