The impact of addition of pantothenic acid at different times during alcoholic fermentation by two different strains of Saccharomyces under fermentative conditions was studied. Two strains of Saccharomyces cerevisiae, EC1118 and UCD522, were inoculated into synthetic grape juice media containing either 50 or 250 mu g/l pantothenic acid. To those media containing 50 mu g/l pantothenic acid, an additional 200 mu g/1 of the vitamin was added either 48 or 96 h after yeast inoculation. While yeast viabilities and fermentation rates were similar for all treatments, H2S production varied depending on yeast strain and time of addition of the vitamin. In general, H2S production was significantly higher for UCD522 compared to EC1118. Furthermore, adding pantothenic acid to deficient musts containing 50 mu g/l resulted in a cessation of H2S production within 24 h of addition. Based on these findings, pantothenic acid can be added before or during alcoholic fermentation as a means to reduce problems such as the formation of H2S. (c) 2007 Elsevier Inc. All rights reserved.