Richard Gawel,* Martin Day, Helen Holt, and Paul A. Smith
*Australian Wine Research Institute, Hartley Grove, Urrbrae, 5064, Australia (richard.gawel@awri.com.au)

Fermenting white juices containing grape solids may contribute to the mouthfeel and therefore the overall complexity of white wine. Chardonnay wines were made from juices containing grape solids (unclarified, 500 ntu and 100 ntu) by cold settling using enzymes, bentonite, and without a settling agent. Other wines were produced on a commercial scale from Chardonnay, Riesling, Viognier, and Sauvignon blanc from unclarified and clarified (200 ntu) juices. The effects of the degree of juice clarity and the method used to achieve it on wine phenolic and polysaccharide composition were determined. Greater juice solids resulted in higher concentrations of wine polysaccharides, which contained a greater proportion of mannoproteins and arabinogalactan proteins. Juice solids content did not consistently affect total wine phenolic concentration; however, the relative contribution of phenolic types to the total varied significantly. Wines from high-solids juices were perceived by a trained texture panel to be more “oily” and “metallic” than those produced from clarified juices. Possible relationships between a wine’s mouthfeel attributes and its phenolic and macromolecular composition are discussed.

Funding Support: Wine Australia