430 CHAPTER XXI 



crystals the peculiar flavour of cane products is seen in Bensen's patent 

 (225 of 1866), which proposes to mix the former with cane molasses. More 

 lately this idea was revived by Winter, who has proposed to use invert 

 sugar syrups which have been exposed to the action of alkalies. 



The Composition of Raw Sugar. — Raw sugar, whether a consumption 

 sugar or one designed for remelting and refining, may be considered as 

 consisting of a crystal of nearly pure sucrose coated with a film of molasses. 

 The quantity of molasses adhering to the crystal wiU depend on the surface 

 area of the crystal, the viscosity of the molasses, and the speed of rotation 

 of the centrifugals in which the sugars are dried. The composition of a typical 

 raw sugar as conceived as consisting of crystal and molasses may be readily 

 obtained. If, for example, molasses contain 20 per cent, water, the per- 

 centage of water in the sugar multiplied by 5 will give the percentage of 

 molasses. At the moment of discharge from the basket 96 test sugars of 

 average size of grain, and under the usual conditions of manufacture, will be 

 found to contain about 1-25 per cent, water, whence the percentage of 

 molasses is 6-25 per cent, and of crystals 93-75 per cent. If this molasses 

 polarizes 36, the polarization of the sugar will be 93 • 75 -f • 0625 x 36 == 

 96-0. Such a sugar would be obtained from a massecuite of 75 purity, 

 and such a sugar is typical of a very great proportion of those that are offered 

 for sale to the refiners. 



After discharge from the basket, sugars of this class will generally be 

 found to lose water and they arrive at the port of destination with but 

 little over i per cent, of water. The actual quantity of water present when 

 melted will depend, of course, on atmospheric and storage conditions at the 

 location of origin, in transit, and at the point of delivery. 



Accepting a raw sugar as constituted of crystal and molasses in fairly 

 constant proportion, its polarization will be dependent on the composition 

 of the molasses, and since {vide Chapter XIX) the percentage of sugar in a 

 molasses increases as the purity of the magma whence crystallized increases, 

 the polarization of the sugar wiU also increase. Thus from a massecuite 

 of 85 purity molasses polarizing 50 may be expected, and if the sugar still 

 contains 6-25 per cent, of molasses the polarization of the sugar wiU, at 

 the moment it is dropped from the centrifugal, be 93 • 75 + o • 0625 X 50 = 

 96-875. The differences found between sugars obtained from h"gh and low 

 purity massecuites will, however, be rather larger than indicated by cal- 

 culation, since the molasses of high purity being less viscous are less incom- 

 pletely removed from the crystal. On the other hand, as the purity of the 

 massecuite falls, so also does the purity of the molasses, and when the sugars 

 are crystallized from massecuites of very low purity the polarization of the 

 sugar falls. In this case, however, there is another factor at work. Such 

 sugars have a very small crystal, and hence the surface area of the crystals 

 is very large, indicating a very large retention of molasses. The sugars 

 obtained from massecuites of about 50 purity boiled blank normally contain 

 about 5 per cent, of water, indicating the presence of 25 per cent, of molasses. 

 If the molasses polarizes 30, the polarization of such a sugar will be 

 75 -}- 0-25 X 30 = 82-5, a normal figure for such material. Sugars of this 

 class are, however, of minor interest, since their production tends to 

 become less and less as improved methods of manufacture become more 

 common. 



The above argument does not take into consideration one point of interest 



