Riesling Wines Made From Must Concentrated by Reverse Osmosis. I. Experimental Conditions and Composition of Musts and Wines

Abstract

Riesling must was ameliorated (concentrated) using reverse osmosis (RO) to three different levels of soluble solids by increments of 2°Brix and the composition of must/wine compared to that of the must/wine ameliorated by chaptalization (CH). RO treatment of the must increased the soluble solids, including the acids. The pH was not affected. The only effect of CH was an increase in sugar concentration. Irrespective of the method of amelioration, the pH was higher and the concentration of the acids were lower in the wines than in their respective musts. The volatile acidity increased linearly over the concentration series for RO but remained constant for the CH series. As the concentration of the sugar in the must was increased by equally spaced increments, the residual sugars in the wines followed the same pattern, since the fermentation was stopped at similar alcohol contents. Results indicate that amelioration of must by RO is an attractive alternative to CH.