Red StarÂ® Pasteur Red (Davis 904), a strain of Saccharomyces cerevisiae, has been derived from the collection of the Institute Pasteur in Paris. It is a strong, even fermenter that produces full bodied reds. This yeast encourages the development of varietal fruit flavors, balanced by complex aromas, especially when using grapes of the Cabernet family. It may be necessary to cool the fermenting must to prevent unwanted temperature increase. This yeast is reported to give character to less robust red grapes, or those picked before optimum development.