In some cases, prune and other fruit juices are added in small quantities to give "mellowness" and flavor.
Blending is also employed in the manufacture of some expensive American whiskies, which are "aged" just as long and at the same trouble and expense as for the best Straight Whisky. The reason, then, is the belief of the manufacturers that greater palatability is thus secured.
The special color and flavor which distinguish American Whisky were originally, and still are largely, due to the use of caramel—and frequently of fruit juices. The same color found in the whisky "aged in wood" to which no caramel or other substance is added, is attributable to the present American custom of using new barrels to store whisky and charring the insides of the barrels to prevent it from acquiring a "woody taste." New uncolored whisky as it first goes into the barrels looks like water, but as the liquor acts on the tannin of the layer under the charred surface of the wood, it changes gradually to very light amber, then to straw color and lastly to a rich amber.
In English, Scotch and Irish whiskies, barley, oats and malt (in varying propor tions—some almost entirely of malt) are the dominating factors. In Scotland, the liquor is generally stored in sherry casks. The "smoky" flavor characteristic of Scotch and Irish whisky was originally caused by the use of peat or turf as fuel for drying the malt, and the force of public habit has resulted in its being continued under more elaborate methods. The best Scotch Whiskies are obtained by blending high-flavored raw whisky with very mild-flavored redistilled whisky and then thoroughly aging.
The five principal stages in the manufacture of whisky are (1) preparing the grain, (2) "mashing," and adding the malt to convert the starch into fermentable sugar, (3) fermentation, to convert the sugar into alcohol, (4) distillation to separate the alcohol from the water and solid matter, and (5) aging.
In addition to the "character" grain—rye for Rye Whisky and corn for Bourbon, etc.—ground barley malt (or in some rye whiskies, rye malt) is used, in American manufacture, in an average proportion of 10% to 20%, occasionally to as high as 25%, according to individual or local custom.
The preparation of the grain means, in a first-class modern distillery, its careful selection (for damaged grain will spoil the flavor of the whisky), thorough "brush ing" and cleansing and, finally, grinding into meal. It is then ready for the "mash" tubs.
A mash tub is generally a wooden or metal receptacle of large size, with apertures for the admission of steam, copper coils for the circulation of cold water and a power driven contrivance (generally called a "rake") to agitate the contents, but in a few distilleries small hand mash tubs and hand paddling are still employed, the distillers denying the advantages of improved equipment.
The tub is half full of water at a temperature of from 140° to 170° Fahr., when the meal is gradually added and well mixed in. The heat is then slowly increased to the boiling point, and the mass—which is nothing more nor less than a gigantic grain "pudding," and has thickened to that consistence—is said to be "scalded" or "cooked." Cold water is added, through the copper coils referred to, until the tem perature is reduced to 150° Fahr. or lower, and then the ground malt and an addi tional 5% or 10% of fresh rye or other meal are mixed in.
Soon after the malt has been worked into the "pudding," the mass begins to soften until it is sufficiently liquid to pass off through a trough or pipe into a wooden tank known as the "fermenter." When the fermenter is a little more than half full of the "pudding" liquid, strained spent beer from a previous distillation is added until the tank is nearly full. This spent beer, familiarly known as "slop" among distillery laborers, is a thin acid liquor, rife with yeast cells and containing some unconverted starch.
The next move in the Sweet Mash process is the addition of some carefully pre pared yeast, and then the whole is left to ferment. The yeast is generally the special secret of each distiller—on its merits and the skill shown at this point, depends much of the quality and value of the product. In some distilleries, prepared yeast is used to the entire exclusion of the "spent beer" addition. By the Sour Mash process, on the other hand, no yeast is used, reliance being placed entirely on the action Of the spent beer.