(57) Packaging of yeast in pliable bags made of material of limited oxygen and carbon dioxide permeability. The yeast is filled into bags made of such material such that the bag is not full to capacity, the bag is sealed hermetically and is then left at a temperature of between 0°-20°C whereby there occurs autofermentation that produces carbon dioxide without inflating the bag. The carbon dioxide causes preservation of the yeast and because of inflation of the bag, the bag is protected against rough handling and squeezing during transportation and storage, whereby the free-flowing properties of the yeast are retained.