Page:Popular Science Monthly Volume 70.djvu/252

248 the names given to these substances would be superfluous; in the language of chemistry they are all sugars, though they are not all sweet. Differing in minor particulars, they all have certain properties in common, and the most characteristic of these common properties is that they each and all may be fermented and will yield ethyl alcohol as one of the products of the fermentation.

The methods for conducting the fermentation on an industrial scale have been carefully worked out, but it is not the intention to enter here into the details of that phase of the subject.

Ethyl alcohol boils at a lower temperature than water, consequently when the dilute alcohol obtained by fermentation is subject to distillation the distillate contains more alcohol and less water than the original liquid. When the alcohol has been concentrated by distillation to about 40 per cent, or 50 per cent, of the total volume of liquid we have one of the so-called spirituous liquors—brandy, whiskey, gin or rum. These liquors owe their individual aromas and flavors to relatively insignificant traces of essential oils and organic esters derived from the particular material which was fermented. Just after they are made they also contain small quantities of distinctly deleterious substances (alcohols other than ethyl alcohol), which taken together are often referred to as fusel oil. These other alcohols should be removed before the liquor is put on the market. The old-fashioned way of removing them was to allow the crude liquor to remain for some years in oaken casks; the wood of the casks gradually absorbed some of the injurious ingredients, while others were oxidized by the action of the air and some coloring matter was extracted from the wood. Such a time-consuming process is not in harmony with modern methods, so we have numerous chemical processes for removing the undesirable constituents. We can impart what color we like with more or less burnt sugar and thus artificially 'age' our spirituous liquors and wines in short order. The number of patents allowed upon processes of this character is surprisingly large. A spirituous liquor is thus cheap stuff at the best, not worth intrinsically a tenth, often not a hundredth, part of its retail price.

The manufacture of whiskey, rum and the like, then, is really a step in the process of the manufacture of ethyl alcohol for commercial use. The alcohol, still too dilute, is subjected to another distillation; it is 'rectified.' This rectification is carried out with the assistance of an ingenious but simple contrivance with the somewhat pompous name of dephlegmator. A dephlegmator consists essentially of a series of chambers, one above the other, each succeeding chamber a