« ForrigeFortsett »
W. T. McConnell
H. G. Chase
Sherman Bros Chicago Fidelity
Dayton, O Silver Star.
Fairport, N. Y De Land Chem...
Fairport, N. Y; De Land Chem., 3
years old Not known.
Alum, phosphate, starch,
SUMMARY OF BAKING POWDERS.
Number of samples analyzed, 70.
Number of samples containing substitutes of lower cost and poorer quality, 63.
A baking powder that contains less than 10 per cent. of carbonic acid is an inferior article in bread-baking. Acid phosphate and starch are not injurious ingredients. A glance at the foregoing table reveals the large percentage of baking powders that are comparatively worthless. One hundred of the most prominent physicians in this state do not hesitate to pronounce alum pernicious in baking powder. A purchaser should have the guarantee of the dealer that no injurious ingredients are to be found, and that the powder has not been so compounded that its leavening power has been impaired or destroyed.
Vinegar is dilute acetic acid containing a varying quan tity of organic matter according to its method of manufacture. It has been known from very early times and is probably coeval with wine. It is mentioned in the most ancient literature. Moses mentions it, and Hippocrates used it in medicine. Its ability to dissolve carbonates was made use of in the earliest times. Cleopatra made use of this property in dissolving pearls and by drinking the solution won her wager of being able to consume the value of one million sesterces at one meal. It is stated also that with it Hannibal dissolved the rocks impeding his march across the Alps. Although vinegar was in general use and was early manufactured, but little was known about its formation. The alchemist Gerber, who lived in the eighth century, first discovered that vinegar could be made stronger by distillation. Valentinus in the fifteenth century knew that by slow distillation of vinegar, first a weak product, then a stronger one is obtained. Stahl and others in the eleventh century produced acetic acid from acetate of copper. Stahl and Westendorf were the first to prepare the acid in a pure state. The dry distillation of wood was known to produce an acid body but it was supposed to be a peculiar acid, and it was not till 1800 that Fourcroy and Vauquelin recognized this acid as acetic acid. It was not until the nineteenth century that the chemical constitution of acetic acid and its relation to alcohol was known. In 1822 Döbereiner discovered that acetic acid was produced from alcohol.
The manufacture of vinegar consists in the fermentation of organic fluids containing alcohol or sugar. Fermenta. tion is a series of decompositions by which the sugar of a liquid is first broken up into alcohol and carbonic acid, with the formation of other compounds in small quantities; and, second, breaking up the alcohol into acetic acid and water.The changes which take place during fermentation are caused by agents called ferments. The organisms producing fermentation are named after certain products which they form in larger quantities. That found in vinous fermentation consists of low forms of vegetable growth called torula or saccharomyces. They are globular or cell shaped in form and multiply by budding. This fermentation is the first that occurs in the process of making vinegar. After the first or alcoholic fermentation is over, a second fermentation commences, resulting in the decomposition of alcohol into acetic acid and water. The ferment which causes this change is a micro organism known as mycoderma acetic. It is widely distributed through the atmosphere, and develops upon the surface of liquid as a thick white skin. Under the microscope this skin is seen to consist of numerous small cells or collection of cells having the general form of the figure eight.
In a more advanced stage of the fermentation they appear as chains and strings of beads. In many of the cells oval forms, slightly contracted, appear. This contraction becomes more marked and the cell finally splits into two new cells. These cells only live for a short time and then sink to the bottom of the liquid and become dormant. In this condition they may remain a long time without destruction. When these dormant cells or germs are placed
on the surface of a fresh liquid and kept at a proper temperature the development of the ferment again begins and continues with great rapidity. Duclaux says: “These little beings reproduce themselves
" with such rapidity that by placing an in perceptible germ upon the surface of a liquid contained in a vat having a surface of one square meter (about one square yard), we may see it covered in from twenty-four to forty-eight hours with a uniform velvety veil. If we suppose that there are three thousand cells in a square millimeter, this will give us for the vat three hundred millions of cells produced in a very short time.”
As the result of many experiments, the conditions most favorable for the production of the vinegar ferment and the conversion of the largest quantity of alcohol into acetic acid are well known. These are:
1. A fluid which, besides alcohol and water, contains nitrogenous bodies and alkaline salts. The quantities of these must, however, not exceed a certain limit.
2.' The fluid must be in immediate contact with the air.
3. The temperature of the fluid and the air surrounding it must be within certain limits (68°-95°F.) The substances used for the manufacture of vinegar are quite numerous. All wines and fruit juices, molasses, beer, solution of glucose, and in fact any fluid containing fermentable sugars. The methods employed in the various processes of manufacturing vinegar belong to one of two classes, the old process of self fermentation, and the new or quick process.
Depending on the material used, many slight modifications are introduced into the old process, the resulting vinegar showing quite different qualities as regards odor and flavor.
Vinegar obtained from dilute alcohol will show a difference in odor depending on the material used in the preparation of the specific alcohol.
Potato alcohol always contains fusel oil and in the oxidation of the alcohol by the vinegar ferment, this oil is oxidized, giving characteristic flavor to the vinegar. Vinegar prepared from wine, fruit, beer and glucose also possesses definite properties as regards odor, flavor, etc.
In preparing vinegar by the old process the first step is the alcoholic fermentation. In case of cider the juice is allowed to stand in casks until it has undergone alcoholic fermentation, and active fermentation has stopped. In most cases it is then racked off into other casks and left exposed to the air till sufficient acidity has developed to render it suitable for use. The above is a long, slow process, several months being required for the preparation of the finished article it being a well-known fact that the vinegar ferment required free access of air. Schützenbach in 1823, conceived the idea that if he greatly enlarged the surface which was exposed to the air, the process of acetification would be greatly hastened. His experinents were successful, and the so-called “ quick process” was soon adopted. The process consists in allowing alcoholic liquid to trickle slowly through beech wood shavings packed into a cylindrical tower, so arranged as to allow a current of air to pass through it. This arrangement presents in a high degree all the conditions required for the formation of vinegar. The vinegar ferment being spread evenly on the surface of the shavings enables the process to take place simultaneously on many thousands of square feet, instead of the limited area of the tank as in the old process. The term quick process is very appropriate; it differs from the old process only in the time required for its execution, the chemical changes being the same in both cases. In carry. ing on the quick process, each manufacturer introduces slight modifications suggested by his experience or convenience, but the following description will give a general idea of the process.
Cider Vinegar.—The cider is put in large store vats and left quiet until the vinous fermentation has taken place. It is then what would be called hard cider and contains alcohol and some acetic acid. It is then known as “stock.” When the stock is ready for the generator it is pumped into the filter. This may be of sand, sawdust or other fil