Materials and methods
The winemaking of Nebbiolo grapes suitable for the production of Ghemme DOCG wine was performed during the harvest of 2008 in “Selector system” tanks. A control tank (A), equipped with the oxycontrol and oxyplus devices, and a test tank (B), equipped with the oxycontrol and oxyfl ow devices have been prepared to evaluate the effi ciency of the oxyfl ow device in term of extraction of phenolic compounds. The method of stirring and aerating the masses for the control tank (A) and the oxyfl ow tank (B) are shown in table 1. The temperature at which the maceration-fermentation took place ranged between 25 and 28°C. The analytical checks performed during the winemaking and at the racking were aimed at measuring the following parameters:
- colour (at the wavelengths of 420, 520, 620 nm);
- phenolic compounds (at the
- wavelengths of 280 and 320 nm);
- anthocyanins;
- tannins;
- general characteristics of the wines;
- combination compounds of the
- polyphenols (copigmentation, cofactors,
- combination indexes of the tannins).
