UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 921 



Contribution from the Bureau of Chemistry 

 CARL L. ALSBERG, Chief 



J&?*'$&U 



Washington, D. C. 



November 9, 1920 



SUGAR-CANE JUICE CLARIFICATION FOR SIRUP 

 MANUFACTURE. 



By J. K. Dale and C. S. Hudson. 



CONTENTS. 



Two methods in general use 



Disadvantages 



New method of clarification __ 



Outline of process 



Industrial development- - 



Experimental plant, 



Operation 



Experiments conducted 



Discussion of results 



Economic considerations. 



Page. 

 1 

 2 

 2 

 2 

 2 

 3 

 3 

 3 

 6 

 7 



Vacuum evaporation in making cane 



sirup 12 



Use of vegetable decolorizing car- 

 toons in connection with infusorial 

 earth clarification 14 



Infusorial earth clarification for 



sugar manufacture 14 



Summary 15 



TWO METHODS IN GENERAL USE. 



Two methods of clarifying sugar-cane juice in the manufacture 

 of cane sirup have been developed and are now in general use in 

 this country. One process, following closely the method of clarifica- 

 tion used in the manufacture of direct-consumption sugars and fa- 

 vored principally in the sugar-cane-producing region of southern 

 Louisiana, where sugar also is manufactured, consists essentially in 

 treating the juice, freshly expressed, with fumes of burning sulphur 

 (S0 2 ) and milk of lime. The juice is heated and the coagulated 

 impurities allowed to settle or removed by settling and skimming, 

 after which the clear liquor is evaporated to sirup in open evapo- 

 rators or vacuum pans or by a combination of open and vacuum 

 evaporation. 



The other and simpler process, used in all cane-sirup-producing 

 regions outside of Louisiana and a small section of Texas, consists 

 in heating the juice and skimming off the scums and coagulated 

 material which rise as the juice becomes hot, forming a thick blanket 

 on the surface. As a rule no chemicals are used in this process, 

 though some sirup makers add a small amount of milk of lime to 

 u make the skimmings rise better." This method requires only the 

 smallest, crudest sort of equipment, but when careful attention is 

 given produces an excellent sirup. 



13702°— 20. 



