Wine-making of High Coloured Wines: Extended Pomace Contact and Run-off of Juice Prior to Fermentation

Abstract

The influence of two different oenological practices (pomace contact time and the running-off of the juice prior to fermentation) on the production of high coloured wines was analysed and tested with two vintages from the years 2001 and 2002. There were assayed three pomace contact times (15, 25 and 35 days) and 15 and 20% run-off treatments. The colour stability of the resulting wines was also evaluated, using an accelerated ageing process. Differences were observed in the colour characteristics between vintages. Larger berries in 2002 led to wines with a lower colour density although the effect of the studied practices was very similar both years. A pomace contact time longer than 15 days led to wines with poor and unstable colour both years. Running-off juice prior to fermentation produced wines with a higher colour density, lower yellow percentage and a higher polymerisation of the anthocyanins. These wines also showed the highest colour stability. The effect of the running-off treatments on wine colour was more pronounced in 2001 than in 2002 due to the different characteristics of the grapes. The extent of this practice must therefore be decided on a year-by-year basis to obtain the best characteristics.