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 ≈13.5, 14.5 and 15.5° 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, saigneé 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 saigneé 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.