788 



SUGAR 



cutting the canes into short piece* and soaking 

 thesr m an equal weight of water : several vessels 

 are employed, the liquor from the first lieing pawed 

 into the second, where it becomes more concen- 

 trated, and so on throughout the series. < '.me 

 juice, pure and simple, of course contains the high- 

 est percentage of sugar, its average composition 

 l>eiiig AS follows : water, 81 ; sugar, 18 ; uncrystal- 

 lisahle sugar, 0-4; other organic matter, IM>; 

 mineral matter, 0'4. To obtain such juice the 

 canes are passed lengthwise through the rollers, 

 usually three in number, which have a combined 

 slow rolling and sliding motion, and great care is 

 t:iki>n to prevent doubling up of the canes and 

 consequent stoppage of the mill. So long as the 

 juice is enclosed within the cells of the plant it 

 never enters into fermentation, but when liberated 

 it rapidly undergoes such change, and it is there- 

 fore necessary for it to be submitted to the pro- 

 cesses of clarification and evaporation without loss 

 of time. Clarilieation, or defecation, is carried 

 put with lime and chemicals, and may be described 

 in general terms as follows. The juice is raised to 

 a temperature of 80 C. (176 F.), and milk of lime 

 is added in quantity sufficient to neutralise the 

 acid, the liqnor then Wing allowed to stand for the 

 separation of the coagulated impurities, some of 

 which subside while others rise to the surface. 

 Sulphurous acid or its salts are also sometimes 

 used, as well as finings, such as clay, which help to 

 carry down the suspended matter. The clarified 

 juice is next run through bag, charcoal, or capillary 

 filters, and then concentrated. This is effected 

 either in open coppers, by means of 111 in evaporators, 

 or in vacuum-pans. The first method leads to 

 lo~s of sugar and discoloration of the product, and 

 is becoming obsolete. The second operation may 

 lie briefly described as passing the juice in a thin 

 layer over the surface of a cylinder (or ' wetzel ') 

 heated internally by steam. The vacuum-pan, for 

 a fuller description of which the student must con- 

 Milt larger works (e.g. S|X>n's Encyrlopaxiia of In- 

 ilii.itruil Arts), is essentially a spherical copper 

 vcel hrated at the bottom by steam-coils, and 

 communicating at the upper extremity by means of 

 a st ill-head with a powerful air-pump which draws 

 off the vapour as fast as it forms, and thereby 

 maintains the boiling-point of the svrup at about 

 66 C. (130'F.). 



The art of nan-boiling consists in concentrating 

 the syrup until minute grains are formed, and then 

 'feeding these by repeated admissions of fresh 

 liquor. The nuimtf-ruite, as the thick mass of 

 i \-tal- is termed, is usually submitted to the 

 action of centrifugal machines which separate it 

 into two portions, dry crystals and syrup or 

 molasses. 



Sucrose is at the present time prepared more 

 extensively from the beet-root than from the cane, 

 anil the article so produced is commonly, but 

 icou-ly. called cane sugar. The beet-sugar 

 industry was first stimulated by Na|ileon I., 

 e-|N'cially during the period when France was 

 deprived of sugar by the Kiiglish blockade, and 

 has assumed immense proportions owing in great 

 measure to the scientific skill that has been ex- 

 pended upon it. The Beet (q.v. , Bftu vutyaris) 

 is indigenous to Kiirope, and many varieties of 

 this plant, as of the sugar-cane, are'known. The 

 juice of tin 1 root contains from 12 to 18 per cent. 

 of crystallisablc sugar associated with various salts, 

 such as the phosphates, oxalates, malates, and 

 chlorides of |M>taxsium. sodium, and calcium, be- 

 sides albuminous. pertinous, and other substances. 

 The plant thrives best in a deep, friable ' turnip 

 loam,' neither too st ill' nor too light, and manuring 

 with phosphatic manures gives the best results; 

 peaty and moorland soils and farmyard manure are 



lens suitable. The seed is usually sown in April, 

 and the crop gathered in autumn before the inci- 

 dence of early frosts. 



Tlie methods for the extraction of the sugar are 

 in the main analogous with those appertaining to 

 the manufacture of sugar from cane-juice. The 

 roots having been harvested are stored until 

 required for use in pits dug in the ground, and 

 covered with straw and earth for protection from 

 frost. They are afterwards taken out and intro- 

 duced into vessels called ' washers,' where they are 

 separated from stones and adhering dirt by a 

 rapid current of water. The roots thus cleansed 

 are then treated for the extraction of the sugar 

 either by (I) rasping and pressing, (2) maceration, 

 or (3) diffusion. The first of these methods con- 

 sists in reducing the roots to a fine pulp by machin- 

 ery, and subsequently squeezing out the juice by 

 powerful presses, the combination representing the 

 cane-mill of tropical regions. The maceration pro- 

 cess is applied to the pulp, which is subjected to the 

 action of water in suitable vessels, the exhausted 

 pulp being afterwards strained from the liquid 

 which now contains the sugar in solution. The 

 diffusion method does not require the rupture of 

 the cells, but utilises the power which sugar and 

 the saline matters, as crystalloids, possess of pass- 

 ing through the unbroken cell-membrane, leaving 

 behind the colloid, albuminous, and pectinous sub- 

 stances. The juice or solution obtained in one or 

 other of these ways is defecated by ' double car- 

 bonation,' according to which lime is first intro- 

 duced in the cold, and afterwards removed by the 

 action of carbonic acid, followed by heating to 

 90" C. (194 F.), the treatment being subsequently 

 repeated upon the decanted juice this time at a 

 boiling temperature throughout. The liquor is 

 next filtered through animal charcoal for the 

 removal of colouring matter, and of the slight 

 excess of lime still remaining, boiled down to a 

 density of 25 B., again passed over charcoal, and 

 then evaporated to a mass of crystals in a vacuum- 

 pan as in the case of cane-juice. 



Sucrose is also made in America from the sngar- 

 maple (Acer saccharinum) and the melon (Cticumi* 

 melp) ; in America and elsewhere from different 

 varieties of sorghum (see Ut'RRA) and from maize 

 (Zea mays) ; and in various tropical countries from 

 i he date-palm and other species of Palmyra. Palm- 

 sugar is derived from the juice which Hows from 

 incisions made in the trunk of the tree. This is 

 very pure, containing less mm -saccharine matter 

 than cane-juice, and far less than beet -juice, and 

 the sugar is obtained by simple evaporation in open 

 nans. Sorghum sugar is extracted and fabricated 

 by processes that am almost identical with those 

 employed in making sugar from the cam-, but the 

 machinery is usually constructed on a much smaller 

 scale. Maple-sugar is manufactured by simple 

 evaporation in iron or copner pans of tlie sweet 

 sap draining from auger holes made in the trunk 

 during the months of spring. In 1891 the total 

 production of sugar of all kinds in the United 

 S t a t es was estimated at , r >30, 7 1 0,000 Ib. 600,000,000 

 Ib. from cane, 29,210,000 from beet, 2,500,000 from 

 sorghum, and S,(K)ii,(KKI from maple sap. The cul- 

 tivation ,,f sugar beet is making progress under ihe 

 allspices of the Department of Agriculture. 



Informer years, before the beet industry as-timed 

 its present enormous proportions, and when the 

 cane was the chief source of supply, sugar w MS to a 

 great extent consumed in the condition in which it 

 arrived from the producing country. This, which 

 was ]Hissible and even pleasant with the sweet 

 and fragrant cane miiscavadocs, became impossible 

 when raw beet-sugar with its unpleasant vegetable 

 flavours was introduced, and the practice of refining 

 all sugars became established. Sugar-refining is 



