Pre-Fermentation Water Addition to High-Sugar Shiraz Must: Effects on Wine Composition and Sensory Properties

Changes to Australian regulations now allow the limited addition of water to high-sugar musts pre-fermentation. In light of these changes, this study explored how water addition affects Shiraz wine composition and sensory properties. Wines were made from grapes at approximate to 13.5, 14.5 and 15.5 degrees Baume. Water was added to musts from the ripest fruit by direct addition, or by using a juice substitution (run-off and replace) approach. To compare the effect of juice run-off independently, saignee treatments were included. Wines made from the fruit that was harvested earlier generally had a lower opacity and higher red fruit aroma as the defining sensory attributes. Undiluted wines made from riper fruit had higher phenolics, and were characterised by dark fruit and dried fruit attributes, and spice, a brown colour and opacity. These attributes were accentuated in wines from the same fruit which received saignee treatments and reduced in all of the water addition treatments. In particular, higher levels of water addition without juice substitution increased the cooked vegetable and drain attributes in the wines. This indicates possible negative effects of larger water additions, such that a low to moderate adjustment in Shiraz winemaking is suggested.