The Commercial Products of the Vegetable Kingdom / Considered in Their Various Uses to Man and in Their Relation to the Arts and Manufactures; Forming a Practical Treatise & Handbook of Reference for the Colonist, Manufacturer, Merchant, and Consumer, on the Cultivation, Preparation for Shipment, and Commercial Value, &c. of the Various Substances Obtained From Trees and Plants, Entering into the Husbandry of Tropical and Sub-tropical Regions, &c.

by P. L. Simmonds

To free it from these constituents, and enable it to yield pure and crystallisable sugar, the liquor, on entering the boiling-house, is received into the first of three clarifiers, of the capacity of from three hundred to a thousand gallons each. Here it is subjected to the action of lime-water, which checks the tendency to fermentation, and neutralises any free acid which it may contain. "The common defection process," says Mr. Fownes, "in careful hands, seems susceptible of little improvement. Many other substances than lime have been proposed and tried with more or less success, some of which, in particular states of the cane juice, may prove very useful; but, for general purposes, nothing seems to answer so well as neutralisation by lime, either in the form of lime-water or milk of lime, added until the slightest possible tendency to alkalinity, as ascertained by delicate reddened litmus paper, is perceived. The juice should be somewhat heated before the lime is added, and afterwards raised quite to the boiling point. The fire is then to be withdrawn, and the whole allowed to rest a short time." Such is Mr. Fownes' description of the process of clarification; to which I will venture to add, upon the authority of those who have experienced its good effects, the joint use of the mucilage of the Guazuma ulmifolia, or gun-stock tree, as it is popularly termed in Nevis from the use to which its timber has been applied. This is the bastard cedar of Jamaica, or Orme d'Amerique, and Bois d'Orme of the French, which may be found described by Lunan, in the first volume of his "Hortus Jamaicensis," page 59, under the name of Bubroma Guazuma.

This tree presents in the interval between its outer bark of sap-wood, a mass of fibrous matter about half an inch in thickness, richly impregnated with mucilage, which is obtained by macerating the fibrous mass, conveniently divided into small shreds, for about twelve hours, in warm water, in the proportion of about two handsful to eight gallons of water. Of this solution, which is of a light, straw color, and somewhat thickened, one gallon is to be added for every hundred gallons of cane juice, after the clarifier has been charged with the proper quantity of lime-water, and has become lukewarm. The mixture should then be stirred, and afterwards allowed to settle till the scum has risen to the surface. The fire must next be cautiously and gradually raised to the point of boiling, when it must again be slackened, and the whole left to stand for about forty minutes, by which time the mass of feculencies will have risen to the surface, when the clear liquor underneath may either be drawn off by a siphon or cock; the whole may be filtered as Mr. Fownes recommends, by which means the liquor would be more effectually clarified, and much, if not all, the subsequent labour of skimming dispensed with. The matter remaining on the filter may be employed, either as a ferment in the still-house, or added to the manure heap. Much of the beneficial effect of the mucilage of the guazuma arises probably from an admixture of tannin, or some other astringent; for I have often been struck with the peculiar whiteness of the potted sugar in the curing-house, in the immediate vicinity of the Banana stalks, resulting, no doubt, from their powerful astringency; and tannin has already been found useful in the manufacture of sugar from beet-root in France, and is no doubt equally applicable to cane-sugar.

The liquor, when clarified in the manner described, must be concentrated, by regulated evaporation, to the degree requisite for crystallisation. This Mr. Fownes advises to be done by steam of a moderate pressure circulating in a spiral of copper-pipe laid at the bottom of the evaporating vessels, which should be large and shallow, and wholly unlike those in present use. Here it may be rapidly boiled down till the heat rises to about 225 deg., without risk of burning. When cold, it should have a density of about 1.38, and mark the 38th degree of Baume's hydrometer; beyond which point of inspissation it would be dangerous to go. The remaining concentration will be most safely conducted in the vacuum pan, where a scarcity of water does not, as in Barbados, militate against its use.

Mr. Fownes exposes the absurdity of using shallow coolers, exposing a large surface, and producing a rapid evaporation, for the process of crystallisation. By the use of the shallow coolers formerly, and, I believe, yet to be found on most estates, from the rapidity of the evaporation, the sugar is obtained in a mass of confused and imperfectly-formed crystals, entangling in their interstices a considerable quantity of molasses, which impairs the color of the product, and escaping slowly, and with difficulty, is, to a considerable extent, lost on the homeward voyage by drainage into the hold, occasioning much positive loss to the owner, and giving the bilge-water a most offensive odor. He therefore recommends the use of deep vessels, and avoidance of all agitation in this part of the process, so as to enable the crystallisable portion of the syrup to effect a more complete separation from the uncrystallisable portion or the molasses. By this simple method, not only sugar of a finer and whiter quality would be obtained, but a large per centage of loss both of crystallisable and uncrystallisable sugar at present caused by the leakage of the hogshead into the hold, would be prevented, not only to the great advantage of the planter, but to the great comfort of the captain, passengers, and crew of the vessel freighted with it.

It is not improbable that, by re-boiling the molasses in the vacuum-pan, and employing tannin in the manner adopted in the process for making sugar from beet-root, from one to five per cent. of crystallisable sugar could be recovered from it, and this per centage might possibly even be found to admit of increase by the further treatment with lime-water and the gun-stock tree s already suggested, for the first clarification of the liquor received from the mill. With this view, Mr. Fownes recommends the substitution of puncheons, or casks, for the molasses cisterns ordinarily employed in the curing-house, to receive the molasses as it drains from the new sugar, and thus retaining it until after the busy period of crop time has closed.

Should sugar of a whiter quality than the ordinary muscovado of commerce be desired, this advantage may be readily obtained, as Mr. Fownes judiciously observes, by filtering the thin syrup, ready for the vacuum-pan, through a bed of fine charcoal, as is done by the sugar refiners, and afterwards washing the crystals of sugar with white syrup, when the molasses has thoroughly drained from them. By this process, which, however, is attended with some increase of expense, and may not, in consequence, be always advisable, muscovado sugar may be obtained, of a quality hardly inferior to that of refined sugar. Mr. Fownes thus sums up the principal points to which he is desirous of calling the attention of the intelligent and enterprising planter.

1. "To obtain, by the use of a properly-constructed mill, the greatest possible amount of juice from the cane."

By this, according to Mr. Fownes, a gain of from 20 to 30 per cent., equivalent to as much marketable sugar, may be obtained without any additional expense; but as, from Mr. Fownes' own showing, there is a residuum of 10 to 15 per cent of liquor obstinately retained by the megass, or cane trash, after the most powerful pressure to which it can be subjected; much, if not all, even of this loss might be prevented by subjecting the megass, on issuing from between the rollers, to the action of water for a brief time, passing it once more through the mill, and adding the saccharine solution so obtained, or that obtained directly from the cane on its first crushing. The water thus employed would serve for many successive portions of megass, until at length it became so richly loaded with saccharine matter as to be worth attention in the boiling-house; or, at all events, it would be serviceable for the cattle, who would fatten rapidly upon it. By this additional process a further gain of at least five per cent. might be expected, raising the total gain from improvements in this first stage of the process, to from 25 to 35 per cent.

2. "To clarify and filter this juice with expedition, and to evaporate it rapidly, either over the open fire or by steam heat, as far as it can be done with safety."

By the use of steam, not only is a vast economy of fuel effected, but the temperature is maintained at a uniform and sufficient standard, and the liquor effectually guarded against the risks of carelessness or ignorance. Coal may be obtained on far cheaper terms, in exchange for produce, from the United States or from Cape Breton, than from England; and as colliers from those quarters would find it their interest to bring cargoes at their own risk, and take return cargoes of sugar, rum, or molasses, at the market price, the planter will be doubly a gainer by the system, obtaining his fuel at a reduced rate, and having his trash and megass left free as manure for the use of his cane fields.