ETHYL ALCOHOL 379 



of inosite phosphoric acid which is a condensation compound 

 of inosite with six molecules of phosphoric acid.* 



MANUFACTURE OF ETHYL ALCOHOL. 



The action of yeast on sugar is made use of in the manu- 

 facture of ethyl alcohol, which substance is prepared from 

 potatoes, rice, and other grains rich in starch. The manu- 

 facture from potatoes is carried out as follows : Potatoes are 

 heated in closed vessels to 125-135° by means of super- 

 heated steam under a pressure of about 3 atmospheres ; by 

 suddenly releasing the pressure the potatoes are burst, and 

 are thus obtained in a finely divided state. The whole mass 

 is then thoroughly stirred up with malt at a temperature of 

 about 60°, whereby the starch undergoes hydrolysis with 

 formation of maltose and dextrin. 



(C6Hio05)n + H^O -> C,2H2,Oij + (C6Hio05)x 

 Starch Maltose Dextrin 



After about one and a half hours the mixture is rapidly 

 cooled to 1 5" and mixed with yeast ; fermentation at once 

 sets in, accompanied by a considerable evolution of heat ; the 

 mixture is therefore cooled artificially, so that the temperature 

 is maintained steady at about 27° -5 -30°. 



During this time the maltose is converted first into dextrose 

 and then into alcohol and carbon dioxide according to the 

 equations : — 



Ci2H2,Pn + H„o = 2CsH,p^ 



CgHiaOg = 2C0H5OH + 2CO2 



In order to convert the dextrin, which would otherwise be 

 lost, into a fermentable substance, the temperature towards 

 the end is maintained at about 26-29° in order to give the 

 malt a further opportunity of hydrolysing the dextrin to 

 glucose, and so rendering it capable of being fermented by 

 yeast. When the fermentation is completed after about three 

 days, the mixture contains about 13 per cent of alcohol by 

 volume ; by distilling the mixture through a fractionating 



* Cf. Neuberg : " Biochem. Zeitschr.," 1908, 9, 557 ; Winterstein : " Zeitschr. 

 physiol. Chem.," 1908,50, 118. See also Plimmer : "Biochem. Journ.," 1913, 

 7.43. 



