Impacts of bottle storage on wine flavor and underlying chemistry

Abstract

Two studies were conducted to address quality degradation and chemical changes, first in wines resealed after opening and second, in wines stored under low oxygen conditions. In the first study, an assortment of strategies for resealing wines were evaluated. Resealing with a vacuum closure resulted in headspace and dissolved oxygen levels that were significantly less than all other closure types at the end of storage. Vacuum treatment had no deleterious impacts on white wine aroma, but resulted in significant decreases in several compounds in red wine. In white wine treatments which had significantly higher final dissolved oxygen than the controls, significant reductions in bound SO2 were observed after three days of storage, but no significant loss of free SO2 was apparent. In some red wine treatments exposed to similar headspace oxygen, significant loss of free SO2 occurred without changes in bound SO2. In the second study, a convenient accelerated aging assay was developed to characterize the potential for H2S to accumulate in wine during low oxygen bottle storage. Wine samples were incubated at 80[degrees]C for 1 hour, then H2S was measured using gas detection tubes. The assay was used to evaluate H2S emergence from hypothesized precursor compounds in three wines. Significant increases in H2S production after accelerated aging were found in at least one wine spiked with cysteine, sulfur dioxide, methyl thioacetate, dimethyl disulfide, and a model quinone-H2S adducts mixture, but not in wines with added glutathione.