This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
The potato is one source of industrial alcohol. In "Farmers' Bulletin 269" of the United States Department of Agriculture H. W. Wiley says:.
The most important of the uses of industrial alcohol as far as the farmer is directly concerned are those included in heating and illumination.
It is quite certain that the use of alcohol motors on the farm will become quite common as soon as the technique of construction is practically complete and the price of alcohol is sufficiently low. Alcohol can be used for all purposes for which gasoline is employed - namely, the driving of wagons, carriages, stationary motors, water pumps, mowing machines, plows, etc. Very little change need be made in the engine of a motor car designed to use gasoline to fit it for the use of alcohol.
Alcohol is used very extensively in the manufacture of dyes and other by-products from coal tar. The manufacture of smokeless powder is one of the industries in which tax-free alcohol is of the highest importance.
One of the most important technical uses of alcohol is in the manufacture of varnishes and lacquers, where the gums which are employed are necessarily dissolved in alcohol. The use of alcohol is extremely important and affects a great many industries.
The ether of commerce, sometimes called sulphuric ether, is manufactured exclusively from alcohol by the action of sulphuric acid and heat.
Alcohol is used very extensively in the preparation of medicines. That great body of remedies known as tinctures is made by using alcohol as a solvent for the active principle of the herbs and plants from which the tinctures are made. The law, however, does not permit the use of denatured alcohol for 'liquid medicinal purposes.'
The substance which is known as imitation silk is really a production from cotton or other cellulose material which, in its finished state, resembles silk somewhat in lustre. It is not silk and hence not even artificial silk. It is a textile product which has the promise of a successful future and is therefore of interest not only to the manufacturer and the consumer but to the farmer who produces the cellulose. Imitation silk is in a measure the same substance as smokeless powder, except that after it is made the nitrogenous constituents are removed, so as to restore the finished product again to the condition of ordinary cotton, devoid of explosive properties. In the making of imitation silk a partial nitrification of the cotton is accomplished in much the same manner as in making smokeless powder. The partially nitrated cotton is then reduced to a paste by solution in alcohol, ether, or other solvent, and in this condition is forced through small orifices, producing fine fibres of a silky lustre.
Dilute alcohol, commonly known as low wines, can be utilized for the manufacture of vinegar. For this purpose the dilute alcohol is made to pass over the fresh shavings of beech wood.
The flavoring extracts of commerce are made largely with alcohol as a solvent."
In "Farmers' Bulletin 268" is the following by the same author:
The term 'industrial alcohol' is used for brevity, and also.because it differentiates sharply between alcohol used for beverages or for medicine and alcohol used for technical purposes in the arts.
The process of rendering alcohol unsuitable for drinking is called 'denaturing,' and consists, essentially, in adding to the alcohol a substance soluble therein of a bad taste or odor, or both, of an intensity which would render it impossible or impracticable to use the mixture as a drink.
The substance should also be of such a character that it is difficult to remove it entirely from the alcohol by any usual process of distillation.
Industrial alcohol, therefore, is a product which is the joint work of the farmer and the manufacturer. The function of the farmer consists in the production of the raw materials from which the alcohol is to be made. The manufacturer takes these raw materials and converts them into alcohol. This is done under the supervision and control of the Bureau of Internal Revenue of the Treasury Department.
The number of substances which have been mixed with alcohol to denature it is extremely large, and that particular denaturing agent should be selected which is best adapted to the special use to which the denatured alcohol is to be put. Among the substances which have been proposed are the following:
Gum shellac (with or without the addition of camphor, turpentine, wood spirit, etc.), colophon-ium, copal resin, Manila gum, camphor, turpentine, acetic acid, acetic ether, ethylic ether, methyl alcohol (wood alcohol), pyridin, acetone, methyl acetate, methyl violet, methylene blue, anilin blue, eosin, fluorescein, naphthalene, castor oil, benzin, carbolic acid, caustic soda, musk, animal oils, etc.
The materials and the quantities which are employed depend upon the purposes for which the denatured alcohol is to be used. There are many technical uses of alcohol, however, in which the pure alcohol only can be employed, and it is a question to be decided by the Bureau of Internal Revenue whether such use of pure alcohol can be permitted under the existing law.
The raw materials from which alcohol is made consist of those crops grown upon the farm which contain sugar, starch, gum, and cellulose (woody fibre) capable of being easily converted into a fermentable sugar. Alcohol as such is not used as a beverage. The alcohol occurring in distilled beverages is principally derived from Indian corn, rye, barley, and molasses. Alcohol is also produced for drinking purposes from fermented fruit juices, such as the juice of grapes, apples, peaches, etc.
The term ' alcohol' as used herein and as generally used means that particular product which is obtained by the fermentation of a sugar, or a starch converted into sugar, and which, from a chemical point of view, is a compound of the hypothetical substance ethyl with water, or with that part of water remaining after the separation of one of the atoms of hydrogen. This is a rather technical expression, but it is very difficult, without using technical language, to give a definition of alcohol from the chemical point of view. There are three elementary substances represented in alcohol: Carbon, the chemical symbol of which is C; hydrogen, symbol H; and oxygen, symbol O. These atoms are put together to form common alcohol, or, as it is called, ethyl alcohol, in which preparation two atoms of carbon and five atoms of hydrogen form the hypothetical substance ethyl and one atom of oxygen and one atom of hydrogen form the hydroxl derived from water. The chemical symbol of alcohol therefore is C2 H5 OH. Absolutely pure ethyl alcohol is made only with great difficulty, and the purest commercial forms still have associated with them traces of other volatile products formed at the time of the distillation, chief among which is that group of alcohols to which the name fusel oil is applied.