SUGAR. —From Beet-root.
801
but in practice this is beset with great difficulties,and the apparent purity coefficient is a more practi-cally useful datum.
Beet-sugar Manufacture.— Although the manu-facture of sugar from the beet {Beta vulgaris) is notpractised in England, and to but a slight extent inany of her colonies, the methods of extracting thejuice and subsequently working it up to sugar havebeen so perfected by the application of the highestskill and science, that a knowledge of them cannotfail to afford some useful and pregnant hints tothe makers of cane sugar. It therefore seemsuseful also to consider this branch of the productionof raw sugar.
The “ sugar beet ” is an improved variety of thecommon white beet; the best varieties of it, suchas the “White Silesian,” the “Imperial,” and“Vilmorin’s Imperial,” are characterized by havinga root of moderate size (1£ to 2^ lbs.), a regularpear or spindle shape, without ramifications orsecondary roots; a somewhat hard, compact, whitesubstance; a small neck or shoulder, which appearsvery little above ground; and above all, a largepercentage of sugar, and a small one of other solublematters. The soil best suited to the growth of goodsugar beet is a deep calcareous loam, free from anylarge number of loose stones, which have a tendencyto make the roots fork, and themselves sometimesget so imbedded in the tissue that they escaperemoval during the cleansing, and then work ruinto the rasp. Though the soil described is the best,the beet is so accommodating.tbat it will flourish inany soil of sufficient depth, if well drained and nottoo peaty. Nitrogenous manures, particularly nitrateof soda, in large quantities produce luxuriant growth,but unfortunately, at the same time, increase theproportion of soluble non-saccharine substances inthe juice to such an extent as seriously to interferewith the subsequent extraction of the sugar. It istherefore advisable to manure the previous crop,say wheat, pretty heavily, and to give the beet itselfnothing but “ superphosphate.”
In order to grow a paying crop of the small roots,which alone are of sufficiently good quality for thefactory, it is found that the best method is to plantvery close—at least twice as close as in the case ofmangolds—then numbers make up for want of size.It must never be forgotten that large roots are badroots, with watery, salt juice. According to someexperiments made a few years ago in England, thecrop varied in different localities from 18 to 30 tonsto the acre, and the roots contained from 8 to 16per cent, of sugar. The present writer carefullyexamined the roots grown in different places in theeastern and southern counties, and found that, inregard to richness in sugar and purity of juice, manywere far superior to those grown and worked inFranco, and fully equal to the best of the German .There is therefore nothing in the soil or climate ofthis country to prevent this useful industry findinga place among us. For details of the method ofculture and preservation of the root the reader isreferred to Stammer’s “Traite Complet de la Fabri-
cation du Sucre.” The quantity of juice containedin beet-root varies but little from the standard of94 per cent.; but the percentage of sugar in thejuice, and the proportion of soluble foreign bodiesassociated with that sugar, are very variable, as shownby the following analyses, quoted from the abovecelebrated authority, as far as the French and German roots are concerned :—
Weight of the Boots(each) in grammes.
Apparent Sugarfrom specificgravity (Per centof Balling).
Per cent ofSugar in Juice ,shown byPolarization .
Per cent, of Sugaron total apparentsolids (coefficientof purity).*
m f 350
18-1
14*9
82*3
§ 1 760
15-7
12*9
82*4
g 3 -j 640
16*0
12*8
79*7
S S 1 632
19*
17*1
90-0
° L 700
16-
13*6
85*0
& { 2500
13*3
10*6
79-7
g £ J 1876
14'2
11*6
81*7
£ § j 1375
10-1
4-6
45-5
^ “ f 523
13-2
12-0
90-9
„ r 682
18-5
15-5
85-4
“ „• 1 961
17*0
14*0
86-0
'tic'o ■{ 680
19*0
15-36
84-4
f! 2 I 650
15*8
12-6
83*2
ft 147
15*3
12*0
82*1
When the purity coefficient falls below 75 per cent. 'the roots are too impure to work with profit.
When the roots are delivered at the factory, thefirst operation is to wash them thoroughly, to removedirt and stones. This washing is effected by the iaid of mechanical washers, consisting of a drum or 1cylinder of iron laths revolving horizontally in atrough of water about half its diameter. The washedroots are then taken up one by one in the hand,examined to see if any stones still adhere, and aretrimmed by a knife, by having the neck or that portionwhich grew out of the ground removed, as well asany small or secondary roots.
There are two principal methods for extracting thejuice from the root: the one based on raspingthe root to a fine pulp and expressing the juice bypressure, and the other on slicing it and extractingthe sugar by systematic soaking in water. The first,which is almost exclusively used in France , is cer-tainly the simplest, and on the whole the best, whenit is not of importance to extract the last trace ofsugar. As, owing to the absence of all duty onsugar, this would be the case in England, it is pro-bable that any one erecting a factory there would findit advantageous to extract as much juice from the [rasped roots as he conveniently could in a rapid andeconomical manner, and to utilize what remained inthe pressed pulp to feed cattle.
The rasp used to reduce the roots to pulp consistsof a large number of small straight saw blades, setalong the face of a drum at about a quarter of aninch apart. This armed drum is mounted on ahorizontal axis, and surrounded with a case whichapproaches the drum closely at its sides, and whichis expanded into a hopper at its upper part. Thedrum is caused to rotate at a velocity of 600 to 1000
* By apparent solids is meant that quantity of soluble bodieswhich is shown as sugar by the areometer, i.e. t the per cent,of sugar shown by the specific gravity float, or the per cent,balling, as given in the second column of the table.