Colour characterization of two‐year old Pinot noir wines by UV‐Vis spectrophotometry and tristimulus colourimetry (CIELab): Effect of whole bunch or grape stems addition

Abstract

Pinot noir wines were made with inclusion of different amount of whole bunches or grape stems: destemmed grapes only (DS), 30% whole bunch (WB30), 60% whole bunch (WB60), 100% whole bunch (WB100), and destemmed grapes with 100% stems added back (DS100). Wines were analysed using modified Somers assay and CIELab method at the end of fermentation and after two years bottle ageing. CIELab analysis showed that DS100 was significantly different from all other treatments at both sampling points, and whole bunch addition treatments (except of WB30) only showed significant colour difference compared to DS treatment after bottle ageing. Total anthocyanins were significantly reduced in stem inclusion treatments at the end of alcoholic fermentation, but after two years bottle aging, only DS100 treatment showed significantly lower anthocyanins than DS treatment. Stem inclusion treatments significantly increased tannin concentration. Total anthocyanins and tannins in wines reduced by 69-71% and 24-31% respectively after bottle ageing.