S P I
S P I
wife fufpected to be great adulterators. The chief temptati- j ons for adulterating are in England, where the duties are high, and where there are various kind.-, of fpirits in plenty to mix with them, as malt, mclaffes, cyder, and fagir fpirits, with all which they arc often fophifticated, and fo dextroufly, as frequently to efcapc all the ways of detection. Rules for dijlillmg brandy Spirits. Brandy, whether made from wine, malt, fugar, or whatever elfe, is a compound confifting of four different parts, which are inflammable fpirit, eflential oil, acid and water.
As thefe feveral parts do not differ greatly in their fpecific gravity, or degree of volatility, a ftrong tumultuary boiling heat will drive them all over promifcuoufiy together. As at the beginning of the operation there ufually arifes more totally inflammable fpirit than water, (o after fome time the ftream contains more water than fpirit. This gives the ' foundation for what the diftillers call low-wines, proof -fpirits, and faints.
The low-wines are the whole quantity of fpirit, ftrong and final], mixed together; proof-fplrit, a mixture of about equal parts of totally inflammable fpirit and water; and faints are what runs after the proof is come off, which is always a mixture of more water than fpirit. The low-wines are commonly rediftiiled, to get rid of the fuperfluous aqueous part, and are thus reduced to brandies, or proof-fpir'its. The faints may alfo be ferved in the fame manner; and by this means the produce of the uiftiilery, which in the ftate of faints, or low-wines, could not be judged of, as to its intrinfic value, is reduced to a certain ffandard, and marketable ftrength.
In the diftilling the fermented liquor, when once the ftream falls from the ftrength of proof-//)/;-/*, there immediately begins to rife with it a coarfe and naufeous oil, which, though not fo communicative as the firft, never fails to impregnate the whole ftream with its flavour. Hence all common fpirits, or brandies, are what the chemifts call di- lute quinteffences ; that is, they are mixtures of the ardent fpirit and eflential oil of the concrete, only here let down to proof with water, and impregnated with a fmall proportion of a volatile acid. As foon as the proof falls off", the liquor grows milky ; that is, the oil, which before remained dif- folved in the ftrong fpirit is let loofe by an over proportion of water, and may be cornmodioufly feparated by the che- mical glafs made for that purpofe.
The common cuftom of the diftillers is to continue the di- filiation, as long as the liquor that runs off will take flame at a candle applied to the vapour of a fmall quantity thrown on the hot head of the ftill ; and indeed there is a certain point of time, after which the fpirit that comes will not pay for the fire and labour, as not more than from a twelfth to a twenty fourth part of the fpirit will come over in th water. With other views, however, fuch as the obtaining a more fixed vegetable acid, and a grofTer eflential oil, the operation may be continued till the danger of an empyreuma comes on.
The matter remaining in the ftill, after the operation ended, has feveral ufes, and may in particular be made to afford Mr. Boyle's acid fpirit of wine. When by repeated diftillation, without addition, any fpirit is entirely freed from its aqueous part, it is then called alcohol, totally inflammable fpirit, reclified fpirit, or, in the vulgar phi'afe, fpirit of iv'tne, On thefe general obfervations, it will be eafy to form fome new practical methods for the improvement of diflillation, as ufed in the way of making inflammable fpirits, or brandies for fale. As the fermented liquor affords different parcels of matter of different degrees of fpecific gravity, and of volatility, when a pure fcparation of the lighteft part is intended, the fire fhould never be railed to a boiling heat, which jumbles and confounds all the parts together, rather than feparates them.
In the chemical way this rule may be practiced to great ad- vantage, but great difficulties will attend the obfervance of it in the common bufinefs of diftillation. To render it more cornmodioufly practicable, thefe two methods may be propofed. i. The encreafing the height of the ftill above the liquor. And 2. the working by a balneum marise, in ftead of a naked fire.
As to the firft method it has been expected, that by raifint the ltill-head to the height of two or three yards above the liquor, a boiling heat would carry up the pure inflammable fpir'tt, without any confiderable mixture of phlegm, and yet continue to run in a full ftream from the nofc of the worm : but this does not anfwer to expectation in all par ticulars, but all the attempts that have been made towards it (hew, that the method is ftill rnrproveable. The fcr- pentine-pipe, ufed in this fort of diftillation by Lcmery, and fome others, though it occafions the fpirit, as it creeps irp, to depofit a great part of its phlegm, yet has this great objection attending it, that the fpirit itfelf will not rife in it without a boiling heat, which never fhould be ufed in a ftmple feparatory diftillation, becaufe it throws up fo much oil, as to foul at leaft the breaft and head of the ftill, and bottom of the pipe, whence it infects the fubfequent fpirit that waflies them.
It is evident that this method mav be brought t
a greater
perfection than it yet -has been, but the other method, by the balneum mariaf, is preferable on fo many accounts, that it is better to bend our thoughts this way in attempting the improvements fo much wanted, and which would be fo be- neficial.
By a proper regulation of the balneum marine, we may hope for a pure fpirit almoft at the firft extraction. Such an ex- pectation will not appear unreafonable to any one, who will compare the fpirit drawn in the common method by the balneum mariie, where the water is made to boil vio- lently all the time, with another parcel of the fpirit pre- pared from the fame fermented liquor by the hot ftill. The difficulties of working from wafh, in this way of the bal- neum marix, are indeed very confiderable, efpecially in re- gard to the common malt-diftillers, ■ with whom cheapness and difpateh are the only things in view ; for to work at the fame time both quick and perfect, is an art not yet learned in the diftilling trade.
The whole application of the balneum marise, in this matter, depends on a luitable engine and apparatus, and perhaps a large and long rectangular boiler might be cornmodioufly turned into the fort of balneum we are recommending ; and tills might be fitted with a great number of low alembics, which would work day and night with a very little fire, and ftill lefs attendance. The contrivance in general is obvi- ous ; but the great art would be the avoiding encumbrance and lofs. A large number of ft ills are abfolutely neceflary, but no worms or refrigeratories are required to them, and by an eafy apparatus, the large number of thefe fmaller frills may be charged" with as much cafe as one great one. When the operation proceeds fo flow, as not to anfwer the cofts, the bottoms of all thefe ftills mav be emptied into one large common ftill, and worked off in the ufual way for a coarfer commodity, that mav afterwards be recti- fied.
In order to procure the fpirit from the fmaller ftills per- fectly pure, the water of the balneum is to be not quite fcalding hot.
By this means, when tried in little, a furprifingly cool and almoft infipid fpirit has been obtained at the very firft ex- traction, though mixed with a confiderable proportion of phlegm, fo that it required no manner of rectification to fit it even for the nicer ufes. The method is curious and ufe- , ful, though tt were found worth while thus only in fmall ; but will become greatly beneficial to the large dealer, if it could be reduced in the fame methods to practice. In the common method of fimple diftillations, all means fhould be ufed to prevent the grofTer eiTential oil from get- ting into the fpirit.
Thefe means have regard to the preparation of the fermented liquor, the regulation of the fire in diftilling, the ufe of percolation, and the keeping out the faints. As to the manner of preparing the fermented liquor, and clear- ing it of its grofs oleaginous feces, before it is committed to the ftill, the beft method is to let it ftand fome time after the fermentation is wholly over, that it may depofit all that it can, and become as thin and limpid as may be; and one great means of arriving at a perfection in this refpect, is the making the liquor fufficicntly thin ; if it be too thick and rich of the ingredient, the fpirit muft be coarfe. The liquor thus prepared, muft never fill above two thirds, at the utmoft, of the ftill. A boiling heat is neceflary in this operation ; but then care muft be taken that this be not car- ried too far, and that the whole proceeds uniformly and regularly. The fire muft be kept as even as poflihle, and never raifed by darts ; for that never fails to throw over the coarfe oil, and foul the Jpirit; fo that, if roTible, the ope- ration fhould begin and end with the fame uniform and in- variable degree of heat.
Another method of keeping the grofTer oil, at leaft in fome degree, from mixing itfelf with the fpirit, is by ftretching a piece of very thick and woolly flannel over the mouth of the ftill, or by fuffering the fteams to pafs through the fame fort of flannel feveral times doubled, and placed at the nofe of the worm. It is furprifmg what a large quantity of grofs fetid, offenfive, and unctuous matter will be thus collected, efpecially in the diftilling of malt fpirits. The faints fhould never be fuffered to run anion o- the finer fpirits, on account of the large quantity of this grofs oil, or greafy matter, they contain ; efpecially if the fire be encreafed, as it ufually is, in order to bring them over. Some of the larger dealers, who value proof more than pu- rity, will always have a dofe of this to give their goods a face, and keep up a head a proper time. This prevailing fondnefs for a ftrong proof, however abfurd in itfelf, is one ' great reafon why the generality of ma\t fpirits are no clearer. This caution of keeping out the faints fhould alio extend to the keeping out a little of the firft running, which alfo, in this operation, is a kind of faints, as containing largely of the oil of the concrete, though much more fubtle than that in the proper faints. A farther regard muft alfo be had to the ftill-hcad and worm, through which the faints have once paHed, as thefe depofit in the head, and along the whole 3 length
