The following are the results obtained by Berkhurts, from the analysis of various samples of genuine and artificial Jamaica rum:[115]—
| Source. | Specific Gravity. | Alcohol by Weight. | Total Solids. | Ash. |
| London | 0·885 | 61·38 | 0·668 | 0·023 |
| Glasgow | 0·875 | 61·38 | 4·800 | 0·089 |
| Bremen | 0·875 | 74·07 | 0·568 | 0·031 |
| Directly imported | 0·910 | 51·33 | 2·047 | 0·098 |
| Artificial | .. | 38·94 | 0·469 | 0·033 |
| Artificial | .. | 58·86 | 0·926 | 0·021 |
The variations in the composition of commercial rum would seem to be so great that little information of value concerning its authenticity is to be derived from analyses of a general character.
Gin.—Genuine Holland gin is a spirit prepared by the distillation of fermented grain infusions (rye and malted barley), flavoured with juniper berries, or oil of turpentine. Formerly the flavouring was directly introduced into the still together with the mash, but the more recent practice is to add salt, water, and juniper berries to the distilled grain spirit, and then re-distil the mixture. Numerous other aromatic substances are likewise employed in the manufacture of gin, among which are coriander, cardamom, and caraway seeds, orris, angelica, and calamus roots, cassia, bitter-almonds, sweet fennel, etc. Cayenne pepper, sugar, and acetic acid, are said to be also frequently added to gin. Gin doubtless possesses more of an artificial character than any other spirit. It is safe to assert that the great bulk of the drink sold under the name is simply grain-spirits flavoured with some of the preceding aromatics. On the other hand, the flavouring agents employed are not, as a rule, harmful in their effects, so that the quality of the liquor is mainly dependent upon the extent to which the spirits used have been rectified. It is difficult to define “pure gin,” since, owing to its compound character, it varies in composition according to the method of manufacture followed by each individual distiller. The variations found from the examination of twenty-five samples of the commercial article, tested by the New York State Board of Health, were as follow:[116]—Specific gravity, from 0·9302 to 0·9694; alcohol (by weight), from 18·64 to 44·33; solid residue, from 0·018 to 0·772; ash, from 0·001 to 0·019.
Adulteration of liquors.—Although it is notorious that the more common varieties of spirituous liquors are sophisticated, the practices resorted to are unfortunately usually of a character that does not permit of positive detection, and, unless an actual adulteration, such as the addition of some substance foreign to the genuine liquor, has been made, a chemical examination alone is frequently inadequate to distinguish between the true and the factitious article. In fact, the ordinary physical qualities, such as odour and taste, are often of greater service in determining the genuineness of distilled spirits than more scientific tests. The most prevalent form of sophistication with brandy, rum, and gin, is their artificial imitations; the direct addition of substances deleterious to health being of comparatively unfrequent occurrence. It is usual to employ a certain proportion of the genuine liquor in the fabrication of its imitation. An apparent objection to this species of adulteration is that grain spirits are liable to be used as the basis of the fictitious product, which is therefore apt to be contaminated with fusel oil, a compound producing toxic effects in a proportion fifteen times greater than ordinary ethylic alcohol.
In the United States, whisky is probably less subjected to serious sophistication than other spirituous drinks. While the blending of this liquor (i. e. the mixing of new and old grades) is almost universally practised by the refiner, and while the retail dealer often reduces its alcoholic strength by the addition of water, there is very little ground for the belief that, in this country, whisky is subjected to noxious admixture to any great extent.
A very large number of recipes have been published for the manufacture of spurious liquors; the following are characteristic, and will indicate their general nature:—
| For Brandy:— | |||
| Cologne spirits (reduced to proof) | 40 | galls. | |
| Oil of cognac | 1⁄6 | oz. | |
| Burnt sugar colouring | 1½ | pint. | |
| Tannin | ¼ | oz. | |
| Brandy essence | 1 | part. | |
| Alcohol | 1000 | parts. | |
| Water | 600 | „ | |
The compound known as “Brandy essence” consists of oil of grapes, 5 parts; acetic ether, 4 parts; tincture of allspice, 1 part; tincture of galls, 3 parts; and alcohol, 100 parts. “Oil of cognac” is a mixture of amylic alcohol and oenanthic ether.
According to M. Duplais, the best imitation of Cognac is the following:—