ALCOHOL— Rum from Beetroot.
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the trade, he is compelled to manufacture it fromnecessity, and the sooner he can turn the article toaccount the bettor he is enabled to bear loss andmeet his engagements.
In France a large quantity of spirit is annuallymanufactured from the molasses of the beet-rootsugar factories, of which a great many exist in thatcountry. The better sort of molasses remainingafter the refining of the sugar of the colonies is toovaluable to be converted into rum, but sometimesthe inferior article is disposed of in this way. Onthe arrival of the molasses at the distillery, they areemptied into largo cisterns perfectly free from anydampness which would cause them to ferment, andhere they remain till required for use. The fer-mentation of molasses presents some difficulties;they must be properly mixed with water in suchproportion that the resulting liquid will not exceed8° of Beaxjme’s areometer, at a temperature of20° C. = 68° Falir., which should always be theheat of the mixture. When too little water is usedthe fermentation sets in too rapidly, the tempera-ture becomes higher, and acetous fermentationspeedily ensues. On the contrary, when too muchwater is employed the fermentation is inactive ; inconsequence of the low temperature a longer timeis required, and generally bad results follow. Theseinconveniences can be overcome by attention tothe directions about to be given.
It sometimes happens that the fermentation ofthe saccharine solution suddenly ceases, and cannotbe revived by an increase of temperature or addi-tion of a stronger solution of molasses. This isowing to the presence of lime and potassa, whichare contained in almost all the molasses of beet-rootsugar, and in consequence of the alkaline reactionimparted by these substances to the liquid, theconversion of the sugar into alcohol is interrupted.This anti-fermenting property of alkaline bodies isvery easily removed; it suffices to add a certainquantity of sulphuric acid to neutralize them andform sulphates, in which state they are inert. Aslight excess of acid might be employed withoutprejudice to the proper degree of attenuation, or tothe taste of the product; for the molasses alwayscontain salts of organic acids, with potassium, &c.,which are decomposed by the sulphuric acid, andthe organic acids are liberated. The sulphuric acidis to be added when the water is mixed with themolasses, and may vary in amount from half a percent, of the weight of the latter, as a minimum, toper cent, as the maximum quantity. Themolasses being comminuted with the water andacid, so that the solution stands at 8° of the areo-meter, about 2 per cent, of their weight of freshbarm, pressed and previously diluted with water,is added; the liquid is then strongly agitated andleft to ferment. The fermentation is made in anumber of tuns whose size corresponds with that ofthe distilling apparatus, and by this arrangementthe distiller is enabled, when the fermentation inone tun is finished, to distil the contents directly.
The fermented wash should never remain longer
than twenty-four hours before it is distilled. Fromthis it is manifest that the distiller should bo fur-nished with as many fermenting vessels as willpermit him to have the contents of one tun dailyready for distillation, and one ready for chargingeach day; the intermediate tuns being in a higherstate of fermentation as their turn brings themnearer the proper time of their being distilled. Allthe tuns should be well covered, to prevent thecontact of the atmosphere and the acid fermentationtaking place.
If molasses be fermonted and distilled merely forthe alcohol which they yield, the preceding direc-tions relative to the proper dilution and strengthupon the areometer answer best; some distillers,however, in addition to the alcohol, extract thealkaline salts ; and in this case the preceding strengthof 8° on the areometer would offer an inconvenience,inasmuch as a large amount of fuel would be con-sumed in evaporating the residuary liquid after thealcohol was expelled. To prevent such expensesfor combustibles, an investigation was instituted tofind out a means for fermenting the saccharine washat a greater density than 8°, and the endeavourproved successful. The high density is 14° of theai'eometer, and in order to ferment such a solutionwithout its passing to the acid fermentation thefollowing mode is adopted:—When a sweet washof 14° B. is set to ferment, the temperature of theliquid rises to 86° Falir. (30° C.) in twenty-fourhours, at which degree the alcohol is readily trans-formed into acetic acid. To oppose the formationof acetic acid, from the high temperature alreadymentioned, it is necessary, as soon as the liquidmarks 76-6° Falir. or 27° C., to divide it into twoequal portions, and add to each half as muchmolasses of 14° strength as it already contains.Previous to mixing the second portion of molasseswith the fermenting liquor, they should be wellagitated with 2 per cent, of their weight of barm.Fermentation is now allowed to proceed withoutapprehension of the temperature rising so high asto favour the acetous fermentation in the liquor.
M. LauGier’s apparatus, which will be subse-quently described, is expressly adapted for thedistillation of fermented saccharine liquors, thoughwine and malt wash are also distilled in it. Itworks upon the same principle as Derosne’s still,under a simpler construction. In France , whereconsiderable quantities of molasses are convertedinto rum, and this apparatus is in operation, thedistillery is divided into the store-room, where thestock of molasses is retained until required foruse ; the fermentation-room, the still-room, and thestore-room for the finished spirit.
The fermenting tuns are of a size to correspondwith the quantity of wash which the still is capableof working daily, and these tuns are worked inrotation, so that one may be worked off and readyfor distillation each day; by this means the fer-mented liquor is prevented from being exposed tothe air, and the formation of acetic acid whollyprevented.