liquors, and, by the relative proportions of its component parts to each other and to the whole mass, eventually determines its quality. In view of the poisonous and deleterious character of fusel-oil, this statement may seem like a confirmation of the frequently expressed opinion that all whisky is essentially injurious in its physiological effect; and, indeed, the fact of its presence in immature whisky has been illogically used as one of the strongest reasons in favor of total abstinence. The argument, however, is no more consistent than would be the indiscriminate condemnation of all fruit because unripe fruit is unwholesome, and a large proportion of it never reaches maturity at all. For note the proviso, "when new." ... Whisky, when first distilled, is entirely colorless, and, with a few local exceptions, is put up in charred white-oak barrels. The gradually deepening amber hue is imparted to it by the thin brown layer of baked wood underlying the charred surface, the charcoal itself—contrary to the general opinion—having no influence in this respect. No extraneous coloring-matter is needed, nor is any ever used by first-class distillers. A very little tannic acid is also extracted from the wood, causing a slight astringency in the liquor. By far the most important changes, however, are the chemical ones which take place in consequence of the presence of the fusel-oil, its constituent acids and alcohols acting and reacting upon each other with the production of fragrant ethers at the expense of the crude re-agents, so that, in a perfectly ripened whisky, the fusel-oil should disappear, with the formation of acetate of amyl (pear-oil), butyric ether (pineapple essence), valerianate of amyl (apple-oil), œnanthic ether (Hungarian-wine oil), etc. Strange transformations these may seem at first sight; but, nevertheless, they are entirely in accordance with chemical analogy, and by no means so remarkable or complex as those by which the volatile alcohol is derived from the solid starch. The development of these fruit-essences is very slow, but may be somewhat hastened by good ventilation and the proper degree of natural heat. It is probable that there are also other subtile changes, the rationale of which has never been explained, but without which the result would be imperfect, as otherwise it would be fair to suppose that the same end could be attained by adding the proper fruit-essences to rectified spirit, whereas in fact the art of the compounder has never been able to produce a good commercial imitation of the genuine article.
The entire series of changes is called "aging," and to it is due the mellowness and aroma which characterize a well-ripened maturity. They can never take place in rectified spirit, as it does not contain the necessary constituents. The length of time during which good whisky will continue to improve can not be limited by any absolute number of years. It should, however, never be used when younger than from three to five years; six years old is still better, and under wise Government regulations it might come about that the usual age will not be less than that.
