This section is from the book "The Complete Cook", by J. M. Sanderson. Also available from Amazon: The Complete Cook.
Spirits and alcohol are obtained by the distillation of fermented articles. The peculiar taste of each depends on the essential oil of the article from which it is prepared being held in solution: therefore, by knowing the nature of its oil, alcohol may be made to imitate any desired spirit. A few drops of nitric ether added to malt spirit will impart to it the flavour of cognac brandy; and two scruples of benzoic acid, mixed with one quart of rum, will give it the taste of arrack. Brandy is generally recommended for the use of the confectioner in making spirits for liqueurs, but a superior article may be made with less expense from rectified spirits of wine, or pure spirit which has neither taste nor smell, as the spirit afterwards drawn will only have the flavour of the articles with which it is required to be impregnated. Rectified spirits may be obtained from the dregs of beer, cider, ale or wine, suitable for any purpose, as well as from brandy.
Spirits rise in the still with less heat than watery infusions, there-fore it is best to distil by means of the bain-marie, that is, by the still being placed in another vessel containing water. This method is more safe, as it prevents accidents, and the articles from being burnt.
Common spirits may be deprived of their impurities by mixing them with an equal quantity of water, and distilling them by a gentle heat, or in a water-bath. Continue the operation until the phlegm arises, which will appear milky and is of a nauseous taste. A great quantity of the oil which it retained will remain in the water. If the spirit was very impure, a second rectification may be necessary, as before. A very pure and tasteless spirit may be obtained by mixing with the spirit, after rectification, one-fourth of its weight of pure dry salt of wormwood or tartar. Let it stand a little time in a gentle heat, and distil in the bain-marie, A small portion of alum being added, prevents any of the salt being brought over with the spirit. The result is pure alcohol. It may be reduced to proof spirit by mixing twenty ounces of alcohol with seventeen of water, by weight.
 
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