234 FAMILY OF SACCHAROMYCETACEAE 



studied by various investigators as Delbriick, Irmisch, Lindner, 

 Reinicke, etc. The Saaz yeast is a bottom yeast by attenuation and 

 ferments dextrose, d-mannose, d-galactose, levulose, maltose, saccha- 

 rose, trehalose, melibiose, raffinose and a-methylglucoside. 



A large number of industrial species (brewery and distillery) 

 related to these species have been described. Some produce a top 

 fermentation while others produce a bottom fermentation. Bau has 

 made four groups: 1, Bottom yeasts of the Saaz type; 2, Top yeasts 

 of the Saaz type; 3, Bottom yeasts of the Frohberg type; 4, Top 

 yeasts of the Frohberg type. The yeasts of the first two groups 

 are characterized by the fact that they give a feeble attenuation, 

 those of the second two groups that they give a strong attenuation. 



Different industrial yeasts have been described by Van Laer, Jor- 

 gensen, Greg, and a few other authors. Among the best known may 

 be mentioned variety II and XII, top distillery yeasts which have 

 been isolated at the Berlin Institute of Fermentology. 



SACCHAROMYCES CARLSBERGENSIS. Hansen 

 Syn. CARLSBERG YEAST. Hansen 



Described for a long time by Hansen 1 under the provisional name 

 of Carlsberg Yeast I, this species has been subjected to a careful 



study by the same author who has given it 

 ^ e name f Saccharomyces Carlsbergensis. 

 This yeast like the Saccharomyces monacensis 

 which we shall describe shortly, has been 



_. used for a long time in Copenhagen breweries. 



Fig. 100. S. carlsbergensts. nA ^ 



A Wort Culture of 24 After culturmg for 24 hours on beer wort 

 Hours at 25 (after Han- at 2 5 C., or after two days at the tempera- 

 ture of the laboratory, Saccharomyces carls- 



bergensis forms a doughy sediment made up of elliptical cells, shaped 

 like an egg or pear. (Fig. 102.) Cells with small points make up the 

 characteristic shape of this variety. The temperature limits for bud- 

 ding on beer wort are 33.5 C. and C. 



In the neighborhood of the minimum temperature, this yeast forms 

 mycelial cells in chains with elliptical cells intermixed. Giant cells 

 are rare. The mycelial cells form between and 9 C. (Fig. 101.) 

 They appear after 2 or 3 months at 0.5 C. At 1 or 2 C. they are 

 formed in a month and a half and a little more quickly at 3 or 4 C. 



1 Hansen, E. C. Recherches sur la physiologic et morphologic des ferments 

 alcooliques, XIII. Nouvelles Etudes sur des levures de brasserie a fermentation 

 basse. Comp. Rend., lab. de Carlsberg, 7, 1908. 



