The Effect of Different Thermovinification Systems on Red Wine Quality

Abstract

The Imeca, Sernagiotto and Gasquet thermovinification plants, all functioning on different extraction procedures, were evaluated over two seasons by comparing the composition and quality of the Pinotage wines produced. The plants tested are installed in different cellars in different production regions with the result that the Pinotage grapes used in these experiments differed in quality and composition. A reference wine from the same batch of grapes processed by each plant was therefore made at the experimental cellars of the OVRI, Stellenbosch against which the wines from each system were compared. Wines from each unit of the different plants were made in order to ascertain individual quality. Big differences of color intensity and total polyphenols of wines from each unit of the Imeca and Sernagiotto, with exception of the Gasquet systems, were observed but only small differences in the alcohol content and total acid and pH concentrations were found. It was not possible to conclude which of the three systems produce the better wines. It could, however, be concluded that the juice from the different units of the Gasquet systems produce wines which do not differ significantly in quality if made separately or mixed and could be marketed as such. However, this could not be said of the wines from the different units of the Imeca or Sernagiotto plants. The only wines of marketable quality are those produced from a mixture of juice of all the units of the plant. Wines from the dejuicer, final press or a mixture of the two are too astringent and intense in color to be marketed as such.