xii, a, 6 Brill and Thurloiv: Alcohol from Molasses 279 



were added, the maximum alcohol content was attained at the 

 end of the fourth day. In Table VI the maximum alcohol con- 

 tent was not reached at the end of the fourth day in a single 

 instance. No effort was made to accustom the yeast to the pres- 

 ence of the iiuoride by culture, antecedent to the experiment 

 tabulated in Table VIII, and this partly accounts for the slow- 

 ness of the fermentation. 



A study of the effect of adding various inorganic salts to the 

 ferment was made. The results of this experiment are recorded 

 in Table IX. The standard solution used here was 200 grams 

 of molasses made up to 1 liter, with the addition of 2 grams of 

 sulphuric acid, and then heated to 70° C. After cooling, the 

 samples were inoculated with pure yeast culture and the various 

 salts were added. 



Table IX shows that magnesium sulphate, sodium chloride, 

 sodium fluoride, potassium phosphate, and sea water do not 

 stimulate the yeast as do ammonium sulphate and fluoride. Sam- 

 ples 2, 3, and 4 gave the largest yields. Samples 3 and 4 had 

 two equivalents of ammonium salts added to them, while 2 had 

 but one. Samples 1, 5, and 9 had one equivalent of ammonium 

 salts added; they excel the remainder of the samples that had 

 no ammonium salts added. This is good evidence of the benefit 

 of adding ammonium salts. Phosphates 16 stimulate yeast, so 

 that its initial activity is increased. They apparently initiate 

 the fermentation, that is, if the materials used in fermentation 

 could be made absolutely free from phosphates, no fermentation 

 would occur. The apparent noneffect caused by the addition of 

 the phosphate in samples 8 and 9 is due probably to the presence 

 of sufficient quantities of phosphates in the original molasses 

 solution to accelerate the fermentation, and the addition of 

 further quantities has no apparent effect. 



The ammonium salts keep the ferment comparatively free from 

 bacteria, because the growth of the yeast is stimulated and the 

 bacteria are crowded out. Ammonium sulphate is as efficient 

 for this purpose as is ammonium fluoride and is much cheaper. 

 Sea water has a deleterious effect on the ferment. 17 The amount 

 of alcohol produced in every case is less than where distilled 

 water alone was used. Sample 7, Table VIII (distilled water 

 used), gave a yield of 70.5 per cent of the theoretical, while 



" Harden, Arthur, Alcoholic Fermentation. Longmans, Green, and Co., 

 39 Paternoster Row, London (1911), 50. 



" The influence of sea water was studied, since salt water from the 

 esteros, on which many of the distilleries are located, is often used for 

 diluting the molasses. 



