The yeast Saccharomyces has evolved towards efficient utilization of sugar. At the end of the alcoholic fermentation of grape juice, typically less than 0.1% sugar remains. Stuck fermentations arise when the yeast cease metabolism of sugar early, leaving a higher concentration than desired and than is normal for a “complete” fermentation under commercial conditions. Sluggish fermentations are defined as those that take an unusually long time to finish, on the order of months rather than two to three weeks. There are many known causes of stuck and sluggish fermentations. Such fermentations are difficult to treat as they are generally not recognized until arrest has occurred. Arrest of fermentation represents an adaptive response of the yeast to stress in the environment. Treatment options usually impact the characteristics of the wine and often lead to reduced wine quality. For these reasons, winemakers would like to reduce or eliminate the incidence of fermentation arrest. Click on the link at right to access the full article