July 2, 1920.] Agricultural Gazette of N.S.W. 481 



Resu t of Two Crushings. 



The yield of juice expressed from the sorghum canes by passing once 

 through the rollers of the experimental mill (Table I) was so low that in 

 four cases, as detailed in Table II, the canes, after being crushed once, were 

 returned to the rollers and crushed a second time. Yields of juice 

 were thus expressed, ranging from 5'3 to 107 per cent., with an average of 

 7 '90 per cent, of the weight of the original canes. The total weight of the 

 juice expressed from these varieties was 29*88, 40-82, 40-78, and 41-28 per 

 cent, of the original canes, and the average yield was 38-19 per cent. Even 

 this yield is very much below the anticipated yield of 65 to 75 per cent. 



When the canes were subjected to two crushings — that is, when the first 

 megass was again' put through the rollers — the average of the three varieties 

 showed that 49-86 per cent, of the total sugars were in the juice, the balance 

 (50-13 per cent.), remaining in the second megass. 



The extractions of 65 to 75 per cent, as mentioned in Bulletin No. 6* have 

 not been realised in this series of trials by crushing, but the above figures 

 might be obtained by diffusion, or a combination of diffusion and cru.shing. 

 With powerful mills, such as are used in sugar factories, it might be possible 

 to increase the extraction to a higher figure than has been obtained with the 

 experimental mill, though experiments made elsewhere indicate that there 

 are serious practical ditficulties. 



In sugar practice it is possible, with modern plant, to get a sugar-cane 

 megass containing as high as 50 per cent of fibre, whereas the average fibre 

 in the sorghum megass was 19-59 per cent., and the less fibre there is the 

 more juice there must be. 



Yields from Crushing Twice. 



The second crushing has therefore resulted in an increased yield of 95 per 

 cent, alcohol of 0-9 gallon to 1-9 gallon, with an average of 1'38 gallon of 

 95 per cent, alcohol per ton of clean canes. At the present market value of 

 alcohol this would be worth Is. lid. 



This would increase the average yield of the total alcohol obtained from a 

 ton of clean canes of the five varieties mentioned in Table II from 5*35 to 

 6-73 gallons. If this increase obtains on the whole series, then the 4-85 

 gallons of 95 per cent, alcohol yielded per ton by clean canes in Table I 

 would be increased to 6-10 gallons as a theoretical yield. Since 100 tons 

 sorghum in the field is equal to 71-87 tons clean cane, 1 ton sorghum in 

 the field would yield 4*38 gallons 95 per cent, alcohol, provided absolutely 

 theoretical results were obtained, and at Is. Ud. per gallon would be worth 

 4s. lid. If, however, only 90 per cent, of the theoretical yield of alcohol be 

 obtained, only 3-95 gallons 95 per cent, alcohol would be obtained, which at 

 Is. lid. per gallon would be worth 4s. 5id. Apparently, then, the cost of 

 cutting, trashing, and transport of the sorghum exceeds the value of the 

 alcohol that has been produced. 



•Bulletin No. 6, Power Alcohol, Advisory Council of Science and Industry, 1918, page 22. 



