Spirits are obtained by distillation of the products of fermentation of different saccharine substances, the alcohol and various volatile substances being separated by distillation. Distillation of malted barley furnishes whisky, malted grape yields brandy, and malted molasses give rum as a distillation product, the flavour in each instance being due to the by-products of fermentation. The by-products can be entirely removed by means of patent stills, leaving an almost pure spirit, known as silent spirit, because its source cannot be traced. Amongst the by-products of fermentation there are alcohols in a higher scries, a mixture of which is known as fusel oil (amyl alcohol). Fusel oil is the last product of distillation, and it is formed especially when spirit is made from grain or potatoes instead of malt. It should be noted that all spirits are free of sugar, and all have a very low degree of acidity: brandy with I gr. per ounce (reckoned as tartaric acid), and whisky and gin having only .2 gr. per ounce.
Whisky is a spirit made from malt, or malt and grain. It is of two kinds. Malt whisky, made in pot stills, and grain whisky, made in patent stills, ordinary whisky being usually a blend of the two. In the case of malt whisky the by-products of distillation give the whisky a raw and disagreeable taste; this, however, gradually mellows, the percentage of alcohol diminishing by 5 to 8 per cent, in the course of a few years. Irish malt whisky differs from Scotch whisky in being prepared from a mixture of malted barley with unmalted grain, the malt not being dried over peat, as in the manufacture of Scotch whisky.
Grain whisky is made from a mixture of grains, barley, rye, and maize, with a little malt to convert the starch into sugar. It is distilled in patent stills, in order to separate to a large extent the by-products of fermentation, including fusel oil. Its method of manufacture makes it soon ready for use, and, unlike malt whisky, it does not improve on keeping. Most commercial whiskies are blends of malt and grain whisky. In recent years, the introduction of patent stills and the extended scale of manufacture has led to an increase in the amount of potato and grain spirit, and it is in these spirits, made from unaltered starch, that fusel oil is specially found. The legal limit for dilution of whisky is 427 alcohol by volume.
Genuine brandy is a product of the grape, and is prepared from the distillation of wine. Good brandy keeps on improving, due to the formation of the volatile ethers. Most commercial brandies, however, are not genuine brandies, but are made from silent spirit, the product of potato or grain coloured with burnt sugar, and flavoured by special essences in imitation of genuine brandy. The alcoholic strength of brandy and whisky is the same. Good malt whisky is more likely to be pure than brandy, and it has the advantage of being much cheaper.
Rum is the product of distillation of fermented molasses obtained in the manufacture of raw sugar, the by-products of fermentation giving rum its characteristic flavour. The best varieties are made from fermentation of the juice of sugar cane; much of the commercial rum is made, as in the case of brandy, from silent spirit, flavoured with special essences, the colour being imparted to it by the addition of burnt sugar. The alcoholic strength of rum is rather greater than whisky - about 50 to 60 per cent, by volume.
Gin is a product of fermentation of a mash of rye and malt, and distillation of the product, juniper berries, a little salt, and occasionally hops being added in the final distillation. Genuine gin is made in Holland. Much of the commercial gin is made, as in the case of brandy and rum, from silent spirit, flavoured with juniper berries, salt, turpentine, etc. The legal strength of gin is 37 per cent, by volume, the usual strength being about 50 per cent. A sweetened and diluted gin goes by the name of Old Tom. Unlike the other spirits, it is not coloured by the presence of oil of juniper or similar oils, which cause a milkiness when diluted with water, since they are insoluble in water. The oil of juniper gives gin distinct diuretic properties.
Liqueurs are spirits sweetened with cane sugar, and flavoured with aromatic or other herbs or essences. The proportion of alcohol in them is high, ranging from 35 to over 55 per cent.; they are usually rich in sugar, such liqueurs as Chartreuse, Kummel, Anisette, and Benedictine having about 30 per cent, of cane sugar in their composition.
Beer is the product of fermentation of malt (barley) with hops. In the preparation of most commercial beers, however, cheaper substitutes for malt are employed. Those include potatoes, maize, and rice. The quality of beer depends largely on the temperature at which the "mashing" is carried out, the higher the temperature the greater the proportion of malt sugar in the beer; also on the temperature at which the fermentation process is conducted; as this is usually high, most of the sugar is broken up, and beer is, therefore, fairly rich in alcohol. In Germany the fermentation is carried out at a lower temperature, with the result that German beers contain less alcohol and more carbonic acid. A light beer is one which contains more malt and less hops, and in its preparation the malt is dried at a higher temperature. Some beers, e.g. India pale ale, are very thoroughly fermented, and therefore contain very little sugar. The essential substances in beer are four in number: alcohols, sugars, free acids, and bitters. The proportion of alcohol varies from about 2 to 7 or 8 per cent, in the stronger British beers (Bass's and M'Ewan's).
Stout and Porter are made in the same way as beer, but the malt is first subjected to a roasting process, which induces the formation of caramel, to which the colour is due. Caramel is added artificially in the preparation of many commercial liquors. Porter is a mixture of dubious composition, containing often liquorice, treacle, linseed, etc.
The approximate composition of beer is given in the following table: -
Per cent, per vol.
English ale and porter . .
The composition of stout is given as follows (Lancet analysis): -
*' Nourishing " Stout.
Extract . . .
Alcohol by volume . .
Acidity . . .
On an average, it may be taken that the chief ingredients of a pint (20 ounces) of good bottled beer is as follows: -
1 fluid ounce.
Free acids .
. 25 grains
1 to 2 „
• 13 "