TY - JOUR T1 - Free Sulfur Dioxide in Red Wine: A Comparison of Analytical Methods in Relation to the Thermodynamic Activity JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 106 LP - 110 DO - 10.5344/ajev.1976.27.3.106 VL - 27 IS - 3 AU - Gary L. Bertrand Y1 - 1976/01/01 UR - http://www.ajevonline.org/content/27/3/106.abstract N2 - The aeration and spectrophotometric methods for determining free sulfur dioxide in red wines are compared on the basis of their fundamental principles, and in relation to the concentration of sulfur dioxide in ethanol-water mixtures at the same partial pressure of sulfur dioxide. The aeration method is shown to be superior, though not without error, estimated to be small and dependent on the concentration of bound sulfur dioxide. Results are high by approximately 1 ppm for red wines containing 200 ppm bound sulfur dioxide. ER -