Gin is a potable spirit flavoured with the volatile products of juniper berries, and often with those of other aromatic herbs as well. It may be either sweetened or unsweetened. The spirit employed is usually patent.still spirit made from cereals, of which maize, malt, and rye are the chief.

Typically, gin is grain spirit which has been rectified once or twice by the gin manufacturer, and then flavoured by actual distillation with the juniper.berries and other aromatics, if any of these are used. Hence one definition of gin which has been proposed is that the article is a spirit distilled from grain, doubly rectified.

and then flavoured by distillation with juniper berries and other herbs. Sometimes, however, the flavourings are separately distilled with a small quantity of alcohol, and the product added afterwards to the rectified spirit.

Fig. 40.   steam.jacketed still. Used for the manufacture of gin (Blair, Campbell & McLean, Glasgow).

Fig. 40. - steam.jacketed still. Used for the manufacture of gin (Blair, Campbell & McLean, Glasgow).

By some it is considered that the rectification should not be so effective as to eliminate all the "grain" flavour of the spirit; but it seems rather doubtful whether any palate except a specially. trained one would be likely to appreciate this flavour in the presence of the pronounced character of juniper oil and some of the other aromatics employed.

Ordinary patent still spirit flavoured with essential oils and not subsequently rectified is often sold as gin, though objection has been taken to this practice by what may be called the orthodox gin manufacturers.

The chief flavourings used other than juniper include angelica, almonds, calamus, cardamoms, cassia, coriander, fennel, grains of paradise, liquorice, orris, and turpentine. This last is said to be used occasionally as a substitute for the juniper. It may be mentioned that a former practice was to grind the juniper berries with the malt, so that they formed a part of the mash during fermentation and were distilled with it.

Makers of gin have their own special recipes, and the various kinds produced have differences of flavour accordingly. Thus in the West of England a favourite make is 'Plymouth' gin, the particular flavour of which is said to be due to the presence of a little ether produced by adding a small quantity of sulphuric acid to the spirit before rectification. The sweetened varieties of gin, e.g., "Old Tom," are made by mixing sugar syrup or" capillaire " with plain gin.

Dutch gin is known as Geneva, Hollands, and Schnapps. The name "Geneva " in this connection is probably derived, not from any association with the Swiss city, but from the Dutch word "jenever," meaning juniper. Geneva is made from a mixed mash of malted barley, rye, and maize in more or less equal proportions, the fermented wash being distilled in a pot-still to form "moutwine ' or "maltwine," which is subsequently rectified and flavoured. The maltwine is made chiefly in Schiedam, and sold to the gin.makers, who rectify and flavour it.

E. J. Parry points out1 that in the analysis of gin there is not much use in determining the "secondary constituents" of the spirit. Except for the slight "grain" character which is said to be desirable, gin is essentially "neutral" alcohol to which the characteristic flavourings are added, and it differs in this respect from brandy, whisky, and rum. The amount of flavouring is a matter of individual preference. Even the kind of flavouring, as well as the amount, is left to the judgment of the maker, subject, of course, to the condition that the essential character of the flavour should be that imparted by juniper.

1 "Food and Drugs," Vol. I, p. 308.

Parry remarks that if an extract of the gin be made, proceeding as in the Allen.Marquardt method but using the lightest petroleum ether obtainable, instead of carbon tetrachloride, the taste of the residue left when the solvent is allowed to evaporate will afford considerable information as to the nature of the essential oil present. If half a litre of the gin be so treated, at least 05 gram of the oil can usually be obtained, and this suffices for determining the refractive index - on the Zeiss butyrometer, for instance. In ten authentic samples examined, the refractive index was never below 14750 (at 20°) and was usually about 1.4770. With turpentine, the value would fall to 1.4725 or lower.

Gin usually contains from 38 to 50 per cent. of alcohol by volume, or 66.5 to 87.5 per cent. of proof spirit. In this country, the legal minimum of alcoholic strength, in normal times, is 35o under proof (65 per cent. of proof spirit); and a good quality gin will approximate to 80 per cent. proof strength. In sweetened gin, the sugar may range from 1 to 6 per cent. or so, but is usually about 2 to 4 per cent.