Influence of wine-making protocol and fining agents on the evolution of the anthocyanin content, colour and general organoleptic quality of Vinhão wines

This paper reports the evolution, over two years, of the anthocyanin content, colour and organoleptic quality of red wines prepared from a single batch of Vinhão grapes by means of three different protocols (maceration/fermentation with conventional pumping-over or in rotary vats, and fermentation after initial carbonic maceration), with and without the use of four different fining agents (polyvinylpolypyrrolidine, gelatin, egg albumin, and casein). Carbonic maceration led to lower anthocyanin levels and less intense coloration than the other two methods immediately following vinification, but during storage the carbonic maceration wines underwent less colour degradation than the others, so that after two years the colour density differences among the three were negligible. Wines treated with fining agents tended to have somewhat lower anthocyanin levels and, especially in the case of PVPP, less intense colouration than untreated wines, and their colour was at best only marginally more stable during storage, but they nevertheless generally achieved higher panel ratings for organoleptic quality than untreated wines, especially as regards taste.