SO₂ in wines: rational use and possible alternatives

Abstract Sulfur dioxide (SO 2 ) has antiseptic and antioxidant properties, and it is the most used preservative additive in winemaking and conservation. Possible allergenic effects of sulfites and consumer demand for “natural wines” have stimulated the interest of producers and researchers to rationalize the SO 2 use. Most Saccharomyces yeasts produce modest amounts of sulfites, so the production of totally sulfite-free wines is a difficult task. The greatest efforts were devoted to limit compounds that permanently bind SO 2 , to increase its molecular form (pH management), and to research new preservative substances of natural origin. Technological advances offer great perspectives, particularly during wine stabilization, filling, and closing of bottles. The significant reduction of residual microbial charge and of the presence of oxygen in bottle makes it possible to greatly reduce the need for preservatives in the final product. Physical methods such as high pressure processing are also alternative proposals because of the capacity for microorganism inactivation.