270 The Philippine Journal of Science im 



mon cleanliness is often strikingly lacking. Neither the inocula- 

 tion of the wort with a culture of yeast in order that the yeast 

 may have a start on the bacteria, nor the distillation of the fer- 

 ment when the alcohol content is at a maximum, is always 

 carried out. It is common practice to allow the wort to become 

 inoculated with yeast from the air. From one to three days are 

 required to bring about active fermentation, and as a consequence 

 the ferment becomes infested with bacteria, which destroy much 

 of the sugar before the yeast crowds them out. No attempt 

 is made to use good water for diluting the molasses, and it is a 

 common practice to use dirty water, thus introducing large 

 quantities of bacteria. Poor yields are obtained when poor 

 methods are used. When the vats and solutions are sterilized, 

 when pure cultures are used, and more care is taken, the cost of 

 handling the solutions will increase, but the greater yield will 

 more than compensate for this. Some figures presented by 

 Owen 7 on the relation of profit to efficiency of fermentation are 

 significant enough to be quoted here. 



Table II. — Profits from the fermentation of molasses, under varying 



conditions of efficiency. 



Theoretical yield. Profit per gallon. 



Per cent. Cents." 



57 -5.5 



60 0.1 



66 1.43 



69 2.0 



75 3.3 



80 4.3 



85 5.4 



90 6.5 



94.7 7.4 



" United States currency. 



This estimate is based on a cost price for Cuban molasses 

 (total sugar as glucose, 55.11 per cent) of 10 centavos a gallon 

 and a selling price of alcohol of 76 centavos a gallon, 180 proof. 

 Theoretically 51.1 per cent of the weight of the sugar is the 

 weight of the resulting alcohol, but in practice this cannot be 

 attained, since some of the sugar is consumed by the yeast and 

 some of it is converted into glycerol, succinic acid, cellulose, etc., 

 so that the highest percentage possible is 94.7 per cent of the 

 theoretical. 



Table II shows that no profit results when a yield below 60 

 per cent is obtained from molasses under these conditions of cost 

 and selling price. A profit of 2 centavos is not obtained until 

 we reach an efficiency of 65 per cent. At 80 per cent, which is 



'Sugar (1914), 16, No. 7, 32. 



