The permanganate solution used is very weak (0. gr. 200 of salt), and of a violet-red color. The technique of the proceeding is as follows: 50 cubic centimeters of the alcohol to be tested are placed in a glass vessel the temperature of which is maintained at 64.40°F. 2 cubic centimeters of the permanganate solution are abruptly added and the time noted to within a second. Discoloration is awaited and as soon as it takes place the time is again noted. The total discoloration of the permanganate is not very marked and passes through intermediate stages; therefore it is preferable not to await complete discoloration but to stop at a pale salmon tint, which tint may be comparatively fixed by a sample of colored liquid (say a solution of fuchsine and chromate of potash).
The comparative times of discoloration obtained by M. Barbet with various commercial alcohols, are as follows:
| Pure alcohol | 43 | min. | 30 | sec. |
| Extra fine alcohol | 5 | “ | 30 | “ |
| Semi fine alcohol | 5 | “ | 10 | “ |
| Medium flavor alcohol (first running) | 5 | “ | 5 | “ |
| Mediocre alcohol | 5 | “ | 11 | “ |
| Medium flavor alcohol (last running) | 2 | “ | 12 | “ |
CHAPTER XII.
Distilling Plants: Their General Arrangement and Equipment.
When we look at the manufactories of to-day with their complicated machinery, their extensive equipment, their great boilers, and engines and their hundreds of employees, we are liable to forget that good work was turned out by our ancestors, with equipment of extreme simplicity and that to-day while there are, for instance, thousands of wood-working mills, complete in every detail and covering under a multitude of roofs every variety of complicated and perfected wood-working machinery, yet there are many more thousands of small plants, comprising a portable boiler, fed with refuse, a small engine and a few saws which are making money for the owners and doing the work of the world.
The reader therefore, must be warned against any feeling of discouragement because of the cost and complicated perfection of elaborate distilling plants. Where the business is to be entered into on a large scale, to take the products from a considerable section of country and turn them into alcohol to compete in the great markets, the best of apparatus and equipment is not too good, but the person contemplating the mere manufacture of alcohol on a small scale, to serve only a small section, must remember that distillation is really a very simple matter, for years practiced with a most rudimentary apparatus and still so practiced in the country districts particularly in the South.
This is well illustrated by the fact that an illicit distiller confined in one of the North Carolina penitentiaries for transgressing the revenue laws, was able while in durance, to continue his operations unknown to the prison authorities, his plant consisting of a few buckets, and a still whose body was a tin kettle, a few pieces of pipe and a worm which he had bent himself. This example is not given as encouragement to illicit or “blockade” distilling but merely to show vividly how simple the rudimentary apparatus really is.
The simplest regular plants, those of the South for instance, comprise a building of rough lumber some thirty feet by twelve wide, with a wooden floor on which the fermenting vats rest and an earthern floor immediately in front of the still and furnace. This is to permit the fires being drawn when the charge has been exhausted in the boiler. The still is of the fire-heated, intermittent variety, such as described on page [35]. It consists of a brick furnace or oven, large enough to burn ordinary cord wood and supporting a copper boiler of fifteen or twenty gallons capacity. On top of this is a copper “head” with the usual goose neck, from which a copper pipe leads to a closed and locked barrel containing raw spirits, this barrel acting on the principle of the condensing chamber shown in the still in Fig. [8]. From the upper part of this barrel, which acts as a concentrator, the vapors pass to a copper worm immersed in a tub of cold water. Here the vapors are condensed and pass by a pipe to a small room, containing a locked receiving tank. This room is kept locked and is under the immediate charge of the Government officer in charge of the still, or, in the case of alcohol intended for de-naturing, the alcohol would pass to a locked tank from whence it would be taken and de-natured under the charge of the proper Government officer.
The fermenting vats may be six or more in number so as to allow the mash in each tank to be at a different stage of fermentation. A hand pump is used for pumping the contents of any of the tanks into the boiler or the still. A hand pump is also provided for supplying water to the vats and condensers.