Correlations between South African Red Grape and Wine Colour and Phenolic Composition: Comparing the Glories, Iland and Bovine Serum Albumin Tannin Precipitation Methods

Phenolic compounds in red grapes might give an indication of phenolic and colour compositions ofthe resulting wine. This work compared the Glories, Iland and Bovine Serum Albumin (BSA) tanninprecipitation methods for phenolic characterization of South African Pinotage, Merlot, Shiraz andCabernet Sauvignon red grape samples (n=31). Significant positive correlations were found for certainphenolic characteristics in the grapes measured by these methods. Levels of phenolic compounds in thegrapes and correlating wines were in line with literature. Merlot samples often associated more with higherconcentrations of seed tannins, which were also reflected in the wines. Significant correlations were alsofound with the colour characteristics of the resulting wines and some anthocyanin related measurementsin the grapes with the Glories and Iland methods, with the latter correlating slightly better. Significantpositive correlations were also found between grape and wine tannins as measured with the BSA method.However, malolactic fermentation changed some of these correlations and this needs to be investigatedfurther. This work might give wine producers as well as wine analyses laboratories valuable informationregarding the suitability of these methods to characterize the phenolic composition of South African redgrapes and their resulting wines