THE ASSAY OF SUGAR HOUSE PRODUCTS. 



Crystallized and Dissolved Sugar. The total sugar in a 

 massecuite or molasses exists in two forms, either separated out as crystals, or 

 still remaining in solution in the necessarily accompanying water; in 

 general two similar juices, similarly treated and boiled to the same water 

 content, will separate out the same amount of crystals, but the actual 

 recovery at the centrifugals may be widely different. For in one case, by 

 skilful pan-boiling, the crystallized sugar is obtained in a form permitting of 

 easy separation from the molasses, and in a second, the presence of fine 

 crystals may cause considerable losses. The determination of the crystallized 

 sugar affords a valuable check on the pan-boiler. 



Vivien's M#thod u . Weigh out about 200 grms. of masse- 

 cuite and place in the funnel of the pressure filtering apparatus, 

 as in Fig. 266, connect the apparatus to a filter pump, and 

 wash with a cold saturated solution of pure sugar and water 

 until all molasses are removed ; transfer the crystals to a tared 

 dish and obtain their weight. Remove about 10 grms. and 

 dry to constant weight to determine the water adhering to the 

 crystals. At a temperature of 84 F., for each one part of 

 water 2*125 parts of sugar are dissolved in a saturated solution. 

 This last determination gives data to calculate the weight of 

 FIG 266 washing syrup which has replaced the molasses ; an example 



is appended. 



Weight of massecuite, 200 grms. ; weight of washed crystals, 175 grms. ; 

 percentage of water in washed crystals, 6-54. Then total moisture in 



washed crystals = - = 12-62, and wash liquor in washed crystals 



= 12-62 X 3-125*= 35-77 grins., and weight of crystals 175 35-77 = 139-23 

 grms., or 69-66 per cent, on weight of massecuite. 



Duponfs Method 1 *. Heat the massecuite to a temperature of 80C. and 

 centrifugal in a small hand machine, the wire basket of which is covered with 

 thin flannel or some similar material ; polarize the molasses and the cured 

 sugar and calculate the percentage of crystallized sugar from the following 



ft ___ /Yl / 



formula : x = *-% where x = weight of crystallized sugar in one part of 



P P 

 massecuite, a the percentage of sugar in the massecuite, p the percentage of 



sugar in the cured crystals, and p 1 that in the molasses. 



This formula is applicable for use on the factory scale, provided no water 

 is used in curing, and that the molasses are filtered through flannel before 

 analysis so as to remove fine crystals ; if water be used in small quantities 

 and if the amount can be calculated, the sugar percentage of the molasses can 

 be corrected for dilution, but in this case the formula will not give results 

 so correct. 



* For a temperature of 84 F. 

 485 



