246 FAMILY OF SACCHAROMYCETACEAE 



colonies develop on wort gelatin with irregular shapes and with the 

 appearance of a network with large meshes. Later the center be- 

 comes compact with irregular contours. The thermal death point 

 for the vegetative cells is about 70 C. This species produces a disagree- 

 able taste in beer and causes very pronounced difficulties. 



SACCHAROMYCES BAYANUS. Saccardo 

 Syn: SACCHAROMYCES n OF WILL. Bay 



This species was described by Will at the same time as the pre- 

 ceding one. He designated it provisionally as Yeast II. It also be- 

 longs to the type ellipsoideus. The cells have the shape of pointed 

 eggs about 7 to 11 JJL long and 5 to 6 ju wide. The temperature limits 

 for the formation of ascospores on plaster blocks are 30-32 and 

 0.5-3 C. The optimum is 24-25 C. At this temperature, the asco- 

 spores appear at the end of 30 hours. They are to the number of 1 

 to 4 per asc and attain 2 to 4 microns in diameter. They germinate 

 usually after having copulated. In old scums, the cells form budding 

 colonies with branches. They are able to reach 30 microns in length 

 and 2 to 3 microns in diameter. The thermal death point for vegeta- 

 tive cells is about 70 C. This species causes cloudiness in beer and at 

 the same time produces a disagreeable aromatic odor, which is similar to 

 that of decayed fruit, and an extremely astringent taste. 



SACCHAROMYCES ILICIS. Gronland 



This species was found by Gronland 1 on the fruits Ilex aquifo- 

 lium. It is a bottom yeast with generally spherical cells. The tem- 

 perature limits for sporulation are 8-9.5 and 36-38. The ascospores 

 are devoid of vacuoles. The scum contains cells which are slightly 

 elongated. Streak cultures on gelatin have a farinaceous appearance. 

 In beer wort this yeast produces about 2.8 per cent of alcohol by 

 volume. Its vegetation gives a very disagreeable taste. 



SACCHAROMYCES AQUIFOLH. Gronland 



This yeast was also found by Gronland in the fruit Ilex aquifo- 

 lium. It is a top yeast with large round cells. The temperature limits 

 for the formation of ascospores are 8-10.5 and from 27.5 to 31. 

 The ascospores possess vacuoles. The scum is made up of spherical 

 and oval cells. Streak cultures on gelatin have variable appearances. 

 This species in wort gives a very disagreeable taste. It produces in 

 wort about 3.7 per cent of alcohol by volume. 



1 Gronland, C. En ny Torula-Art og to nye Saccharomyces-Arter Vidensk. 

 Med. fra den Naturh. Foren, Copenhagen, 1892. 



