362 ODOROGRAPHIA. 



been ascertained by Henninger, does not appear to cause any 

 unpleasant flavour in brandy when existing to the extent above 

 recorded and in association with the other flavouring constituents. 

 On examining, for comparison, the commercial brandies (from 

 maize, beetroot and potato), I have found propyl alcohol, amyl 

 alcohol (active and inactive), pyridine, a compound boiling between 

 180^-200^ C. (collidine ?), and isobutyl alcohol, but no trace of 

 normal butyl alcohol." 



" The presence of normal Ijutyl alcohol in brandy leads me to 

 suppose that it is the usual product of alcoholic fermentation wdien 

 elliptical yeast is the fermentive agent, and that isobutyl alcohol 

 is formed when fermentation is developed by beer yeast. To test 

 this theory I fermented 100 kilos of sugar molasses with wine lees 

 which had been dried in the air, and from the resulting 19 litres of 

 alcohol of 92^ I extracted an oil of agreeable odour, very different 

 from that extracted from the commercial oil of the distilleries and 

 containing normal butyl alcohol mixed with amyl alcohol. This 

 oil resembles that which is distilled from new wine. This experi- 

 ment proves therefore, that elliptical yeast generates secondary 

 products different to those produced by beer yeast. The odour 

 wliich merchants call the odour of " trois-six " observable in 

 ordinary commercial brandy, is due to the presence of isobutyl 

 alcohol, which the process of rectification, as carried out at the 

 distilleries, cannot remove. Isobutyl alcohol also has an 

 unpleasant taste, wdiile the normal butyl alcohol possesses the fine 

 rechercMe flavour so much admired by judges of brandy." 



The memoire hy Ordonneau in the " Comptes Eendus " above 

 referred to, concludes by stating that all saccharine solutions 

 fermented with elliptical yeast will yield alcohols of good flavour 

 and odour. This yeast is as easily cultivated as beer yeast. It is 

 technically known as a " bottom yeast." It acts vigorously at 28^- 

 32^ C, and does not appear to degenerate after many cultivations. 

 Its appearance under the microscope is delineated in Pasteur's 

 work " On Permentation." 



Experiments have been made to determine whether this 

 elliptical yeast {saccharowyces ellipsoideiis) is merely a form of beer 

 yeast determined by the influence of a special medium, the must of 

 grapes, and if so, whether it could be induced to return to its 

 primitive form. The experiments consisted in sowing the ferment 

 in different media, among others in an unmalted barley-wort to 



