This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
To bottlers who are desirous of obtaining pure gas for their carbonated beverages, and more especially for the delicate mineral waters, where purity is most needed, we should recommend the use of either of the above-mentioned chemical solutions, renewing them as well as the water after every operation, when they will soon observe a great change in the quality of their carbonated beverages, of which carbonic acid is and will ever remain a great factor. Those who possess more than one purifier, we should advise to use the remedies as follows: Two purifiers - put in the first one chunks of marble and water as already directed, or two to three ounces of carbonate, or, better, bicarbonate of soda previously dissolved in some water, and in the second put a mixed solution of about three ounces of sulphate of iron and two ounces of bicarbonate of soda. The quantities may be increased or diminished proportionally, as circumstances may require or permit.
If bituminous or animalic odors are to be guarded against more cautiously, add to second washer also about one-quarter of an ounce of permanganate of potassium, previously dissolved in cold water. Three purifiers: put in first and second washer the same ingredients, except the permanganate of potassium, which put here in the third washer or coarse animal charcoal instead. Also a few drachms of solution of salicylic acid may be added to either one of the purifiers.
Where two or but one purifier is available, this chemical purification might be carried out in one or two of them by adding either one or several of the chemical remedies combined in one or two washers, but of course this would only do for a smaller manufacturing concern. Where a larger business is carried on separate purifiers and, if necessary, special cylinders (repurgators) are highly recommended.
When muriatic acid instead of sulphuric acid is employed in generating the carbonic acid gas, we recommend that in at least two purifiers soda solution be used to ascertain the neutralization of eliminated chlorine gas.
We leave it to the good judgment of the enterprising bottlers to make use of those chemicals in manner and proportion to suit themselves; but remind them of the fact, that when a bottled beverage is opened, part of the carbonic acid gas escapes violently. If bad odors are mixed with the carbonic acid, the escaping gas carries them along into the atmosphere, thus making their presence at the first moment known to the consumer.
Even traces of bad odors will thus be sensible, and this should be convincing of the absolute necessity of carefully purifying the carbonic acid gas. In gasometer tanks the water is also used for washing the gas, and where nothing but pure water is used, some solution of the aforesaid chemicals may be added to aid in the chemical purification of the carbonic acid gas.
The purification of carbonic acid is never perfected without the removal of atmospheric air from the apparatus. It is well known to chemists and practical men that atmospheric air is to be found in water used for charging the generator, the purifiers and the fountains, and above the surface of it fills the empty space of the apparatus. In practice the atmospheric air is "blown off" after the apparatus is charged with more than 60 lbs. of pressure, and the principles of this are explained or another page, to which we refer. If any considerable quantity of air re mains in the water it seriously interferes with the success of the car bonating process.
The early makers recognized this fact, and were careful to pump out the atmospheric air from each charge of water before forcing in the gas. This is still done by some of those who follow the semi-continuous or intermittent plan; however, the pump can be dispensed with. In older to displace and remove the atmospheric air that is absorbed by the water, it is more practical to charge the liquid first and then blow off under pressure as already directed.
The displacement of the atmospheric air does not take place suddenly with exactness; it is therefore better, even necessary, to blow off several times to assure the removal of atmospheric air. To assure a con-Urinous sparkling after the carbonated beverage has been poured into a glass, that vivid brilliancy so much liked and admired, it is absolutely necessary to remove the atmospheric air at the beginning of the impregnation, otherwise the beverages will soon be flat.
The superiority of the beverage amply repays for the trifling loss of gas, and this mode of removing the atmospheric air, when proper attention is paid to it, will sufficiently purify the carbonic gas.
With apparatus constructed after the continuous system, English plan, manipulate as follows: 1. Blow off the air from the gasometer by way of the cock attached to the top of the gasometer bell; and 2, blow off the first parts of the saturator or condenser, which always contains some air, when commencing an operation. However, the beverages made with the continuous system nevertheless will contain some atmospheric air as the water, continuously drawn, keeps always a certain percentage of air absorbed, which is in the course of the fast process with this system not displaced or blown off and consequently enters into the beverage.
Messrs. Howard & Fardon, London, England, were granted a patent in 1878 for an invention, the main object of which is to manufacture carbonated waters by a continuous process, in such a manner that the air naturally contained in the water used in the manufacture shall be withdrawn by suction during the process, and the water thus deprived of its air be forced into one or more condensers simultaneously with the carbonic acid or other gas. The description and illustration of this invention, as arranged on continuous apparatus by the owners of the patent, Messrs. Hay ward, Tyler & Co., to whom we are especially obliged for a copy of the latter's patent, we will find in Part III. on Apparatus.
In concluding this article on the different methods of purifying carbonic acid gas and on the removal of atmospheric air, we may fairly say, that the average bottler is generally contented with passing the gas through the water in purifiers without any additional precaution in purifying it, and frequently lays the fault of an inferior beverage to other materials, but not to what he omitted. The carbonator who strives to bring his manufacture as near as possible to perfection and purity will certainly take advantage of all means offered and disclosed to him.