Effects of Sulfur Dioxide and Polyvinylpolypyrrolidone on the Flavor Stability of Beer as Measured by Sensory and Chemical Analysis

Abstract

A sensory panel was trained to articulate and quantify aged characters in ales and lagers. Key terms used to describe aging were hay/straw aroma, cardboard flavor, and apple/wine flavor. The panel was employed to detect the merits of adding sulfur dioxide (SO2) at levels that would be permissible without labeling in the United States. Although some benefit was observed, few of the differences were robust statistically. The observations made by the panel were compared with the observed impact of SO2 on total levels of carbonyl substances measured in the same beers. The reduction in carbonyls was similar irrespective of whether SO2 was added before or after accelerated aging regimes, whereas the limited benefits seen via sensory evaluation were only observed for sulfite addition prior to aging. It is inferred that the limited protective action of SO2 is as an antioxidant rather than as a binder of carbonyls through adduct formation. The taste panel was also used to demonstrate that the partial removal of polyphenols by polyvinylpolypyrrolidone was without any significant effect on the flavor stability of the beers studied.