ALCOHOL FROM MOLASSES.—Another common source of alcohol is molasses or treacle. Molasses is the unerystallizable syrup which constitutes the residuum of the manufacture and refining of cane and beet sugar. It is a dense, viscous liquid, varying in colour from light yellow to almost black, according to the source from which it is obtained ; it tests usually about 40° by Baume's hydro meter. The molasses employed as a source of alcohol must be carefully chosen ; the lightest in colour is the best, containing most uncrystallized sugar. The manufacture is extensively carried on in France, where the molasses from the beet sugar refineries is chiefly used on account of its low price, that obtained from the cane sugar factories being considerably dearer. The latter is, however, much to bo preferred to the former variety as it contains more sugar. Molasses from the beet sugar refineries yields a larger quantity and better quality of spirit than that which comes from the factories. Molasses contains about 50 per cent. of saccharine matter, 24 per cont. of other organic matter, and about 10 per cent. of inorganic salts, chiefly of potash. It is thus a substance rich in matters favour able to fermentation. When the density of molasses has been lowered by dilution with water, fermentation sets in rapidly, more especially if it has been previously rendered acid. As, however, molasses from beet generally exhibits an alkaline reaction, it is found necessary to acidify it after dilution ; for this purpose sulphuric acid is employed, in the proportion of about 4i lb. of the concentrated acid to 22 gallons of molasses, previously diluted with 8 or 10 volumea of water, Three processes are thus employed in obtaining alcohol from molasses : acidification, and fermentation. The latter is hastened by the addition of a natural ferment, such as brewers' yeast. It begins in about eight or ten hours, and lasts upwards of sixty.
In Germany, where duty is imposed upon the distilleries according to the capacity of the fer menting vats, the molasses is not diluted to such an extent as in France, where the duty is upon the manufactured article. In the former case the liquor, before fermentation, tests usually as high as 12° &Amid, whereas in France it is diluted until it tests 6° or 8°, a degree which is much more favourable to rapid and complete fermentation. In consequence of this difference in the concentra tion of the unfermented liquor, the degree of temperature at which the process is begun is higher in the case of the strong liquor than when it is more dilute. In Germany, the temperature at which fermentation begins is about 25°, and this is raised during the operation to 30°, whilst in France a much lower temperature suffices. Moreover, owing to the enormous size of the French vats, the
temperature rises so quickly that it must be moderated by passing a current of cold water through a coil of pipe placed on the'bottom of the vat. Two cwts. of molasses at 42° Baumd will furnish about 6 gallons of pure spirit. The spirit of molasses has neither the taste nor the odour of spirit from wine ; it is sweeter, and when the distillation and rectification have been properly conducted, it may be considered as a type of alcohol in its purity, for it has neither taste nor any peculiar aroma. In this state it is called fine spirits, and may be employed in the manufacture of liqueurs, for improving common brandies, and especially for refining the trois-six (rectified spirit) of Montpellier. In those districts of France where the beet is largely cultivated for the manufacture of sugar, and the molasses is converted into alcohol, the waste liquor is made a source of no inconsiderable profit by concentrating it and incinerating the residue, from which is obtained, for the use of the soap-boiler, a caustic potash of superior quality. In addition to the alcohol, good beet molasses will yield 10 or 12 per cent. of commercial, or from 7 to 8 per cent. of refined potash. In addition to this a method has lately been proposed by M. Camille Vincent of collecting the ammonia water, tar, and oils given off when this residue is calcined, and utilizing them for the production of ammonia and chloride of methyl, which latter substance possesses considerable commercial value. The pro cess has been made the subject of a paper read by Professor Roscoe before the Royal Institution, who prophesies for it the most complete success when tried on an industrial scale. " Chloride of methyl," he says, "has up to this time, indeed, not been obtained in large quantities ; but it can be employed for two distinct purposes: (1) it serves as a means of producing artificial cold ; (2) it is most valuable for preparing methylated dyes, which are at present costly, inasmuch as they have hitherto been obtained by the use of methyl iodide, an expensive substance." Besides the molasses of the French beet sugar refineries, large quantities result from the manu facture of cane sugar in Jamaica and the West Indies. This is entirely employed for the distilla tion of rum. As the pure spirit of Jamaica is never made from sugar, hut always from molasses and skimmings, it is advisable to notice these two products, and, together with them, the exhausted wash commonly called dunder.