Behaviour and characterisation of the colour during red wine making and maturation

During winemaking and ageing, the colour of red wine evolves from the initial purple-red hues of young red wines towards more red-orange ones. Simultaneously, a modification in the pigment profile takes place. The stability of pigments isolated from red wine has been usually studied in model solutions. However, studies carried out on wines are scarce. The objective of this work was to analyse the changes in composition, colour and stability in relation to pH and SO2 that take place in a red wine during winemaking and maturation. For this purpose, samples of red wine from Tempranillo grapes were collected periodically during 18 months and submitted to chromatic analysis using the CIELAB and CIELUV colour spaces and high performance liquid chromatography–diode array detection coupled to a mass spectrometer analysis (HPLC–DAD–MS). The results obtained showed the existence of processes capable of causing quantitative and qualitative changes in the colouring material of the wine. These changes, in spite of the relatively short time considered, are sufficient to cause changes of colour that can be perceived by the human eye and lead to the formation of pigments that are more stable against pH and against bleaching by SO2 than the original anthocyanins.