Colour dynamics in wines made from co-ferments of Vitis vinifera L. Syrah and Viognier

Anthocyanin-derived pigment profiles in a series of 100% Vitis Vinifera L Syrah and 2, 5, and 10% co-ferments with crushed destemmed Vitis Vinifera L Viognier were compared, using spectroscopic, protein precipitation and HPLC methods. The extent of co-pigmentation was highest in the younger wines and declined a month after fermentation and further for the year-old wines. A higher degree of co-pigmentation matched a higher colour density expression. Anthocyanin self association co-pigmentation peaked at day 6 followed by co-pigmentation due to the reaction between anthocyanins and other polyphenolic co-factors peaking at day 12, while polymeric pigment became significant after day 19. The treatments with the higher co-winemaking additions showed the highest % CA colour levels and the fastest rates of % PA and % LPP colour formation. Nevertheless, over the course of the study the control, with Syrah only, was not consistently different in colour enhancement due to co-pigmentation than the Syrah co-fermented with Viognier. The phenolic profile of the added Viognier did not contribute sufficient co-factors to the Syrah ferment to bring about co-pigmentation colour enhancement.