Winemaking of Sangiovese grapes with and without the addition of different oenological tannins in order to increase the colour intensity of Chianti wine

The objective of the paper is twofold: a) to verify the influence of the addition of enological tannins of different botanical origin to the must on the phenolic extraction during grape maceration; b) to develop a specific RP-HPLC analytical methods for evaluating the tannin fingerprint of a wine. In order to evaluate the effect induced by the addition of three enological tannins of different botanical origin (oak wood, grapes, quebracho) and chemical compositions (hydrolysable, proanthocyanidinic and a mixture of proanthocyanidinic and hydrolysable tannins), four vinifications of Sangiovese grapes (three with each commercial tannin, the forth without addition) were performed in small stainless steel tanks in a winery of Chianti region. The time evolution of the accumulation in the liquid phase of different phenolic compounds (total phenols, proanthocyanidins and anthocyanins) was evaluated as a function of the enological tannin added to put in evidence if some characteristics of wine, such as color stability, are improved. While the values assumed by the functional parameters of the kinetic equation used to describe the evolution of total phenols with the extraction time did not seem to diversify significantly as a function of the tannin added, this was not verified for anthocyanins which appeared to be affected by the enological product added. The analytical methods for evaluating the tannin fingerprint by RP-HPLC was set up, so they could be applied during the next crop season.