12 BULLETIN 921, U. S. DEPARTMENT OF AGRICULTURE. 



In infusorial earth nitration about 45 pounds of press cake were 

 obtained per ton. Considering the ease and rapidity with which this 

 cake can be washed, there seems to be no reason why the sugar 

 content should not be reduced easily to less than 1 per cent. The 

 loss then would amount to about 0.45 pound of sugar <ar about 0.06 

 gallon of sirup per ton. On the basis of $1 sirup, this would be a loss 

 of only 6 cents per ton. The difference in the losses, 21 cents per ton, 

 would more than pay for the difference in the cost of the clarifying ma- 

 terials. However, the principal advantage would be in the improved 

 flavor of the resulting sirup, which when properly evaporated com- 

 pared favorably in color with the leading brands of Louisiana cane 

 sirup on the market. The flavor was, in the opinion of the writer 

 and others, milder and more agreeable, lacking the somewhat tart 

 and metallic flavor of the usual Louisiana type of sirup. 



The manufacture of sirup by the clarification method just de- 

 scribed requires a larger outlay of capital and somewhat larger 

 operating cost than when the manufacture is by the simple process 

 of skimming and evaporation in open evaporators. The advantages 

 are that a cleaner and better product can be obtained, the capacity 

 of the evaporators can be increased — for it is not necessary to retard 

 the evaporation as is at present the case to* permit of proper skim- 

 ming — the yield of sirup can be somewhat increased owing to 

 the fact that all the scums and dregs are obtained in a hard, compact 

 mass instead of in a thin mush containing a large amount of juice, 

 and finally that the quality of the resulting sirup will be more uni- 

 form and will depend less upon the individual sirup maker and the 

 care taken in skimming. 



VACUUM EVAPORATION IN MAKING CANE SIRUP. 



Though no exact information is available on the subject, it seems 

 to be the general opinion that open evaporation is necessary in order 

 to produce the finest-flavored cane sirup, some maintaining that 

 the best flavor or aroma can be obtained only by cooking the juice 

 in open evaporators. Some assert that sirups made in multiple- 

 effect evaporators and vacuum pans are darker than those pro- 

 duced by rapid evaporation with live steam in open vats, while 

 others state that a very high grade of sirup can be obtained, even 

 though the evaporation is conducted mainly in vacuo, provided at 

 some stage of evaporation it is boiled a few minutes in an open 

 vat or brush pan. For the larger factories it is undoubtedly true 

 that from an economic standpoint it is desirable to carry out as much 

 of the evaporation as possible in multiple effects or vacuum pans, 

 since evaporation can then be effected largely by exhaust steam. 

 Even when it is necessary to use live steam the fuel consumption is 

 not so great as in the case of open evaporation. 



