1490. To Restore Rancid Fat or Oil

1490.    To Restore Rancid Fat or Oil. Another method is to thoroughly wash them with hot water, frequently renewed, or to blow steam through them, until the desired effect be produced. Air freely employed for some time, instead of steam, succeeds admirably with many oils, and its use has the advantage of not introducing moisture into the article. Another method is to boil oil or fat, for 15 to 30 minutes, with a little water and calcined magnesia.

1491. To Prevent Oils and Fats from Becoming Rancid

1491.    To Prevent Oils and Fats from Becoming Rancid. The tendency of oils and fats to become rancid may bo prevented, or greatly retarded, by artificial means. One of the simplest methods is to dissolve about 2 per cent, of gum-benzoin (in fine powder), or about one per cent, benzoic acid, in the oil or fat, by the aid of a gentle heat. This addition renders oils, pomades, ointments, etc., peculiarly soothing to an irritable or highly sensitive skin. It should be done before the addition of the scents. When the preparations are intended for exportation to hot climates, the percentage of the gum or acid should be somewhat increased. This is the plan generally adopted by the manufacturing perfumers and druggists. In the wholesale trade, carefully rendered lard, suet, etc..; simple pomades and oils, so prepared, are now common articles of stock and sale.

1492. An Excellent Preventive of Rancidity in Oils, etc.

1492.    An Excellent Preventive of Rancidity in Oils, etc.. Nitric ether, or its alcoholic solution (sweet spirits of nitre), is highly recommended as a most effective preventive of rancidity. It is said that a few drops of the ether will effect this object, and will even remove the disagreeable odor of rancidity when present. Oil so treated, after being heated to remove the alcohol, when the solution has been used, is quite bright, clear, and scentless, if it were originally so. Poplar-buds, crushed and digested at a gentle heat, in oil or fat, will also remove, or greatly retard, its tendency to become rancid. Patty bodies in a globular state may be kept a long time without becoming rancid. This peculiar state can be imparted to fatty matters by melting them at 130° Fahr. and adding a small quantity of yolk of egg, or bile, or albuminous substances, or best, a solution of alkali (composed of 5 to 10 parts for every 100 of oil), at the same temperature. The whole is then agitated for some time to bring the fatty matter into a globular condition.

1493. To Prevent Fats and Oils from Becoming Rancid

1493.    To Prevent Fats and Oils from Becoming Rancid. Heat the oil or melted fat for a few minutes with powdered slippery-elm bark, in the proportion of 1 drachm of the powder to one pound of fat. The bark shrinks and gradually subsides, after which the fat is poured off. It communicates an odor like that of the hickory-nut. Butter thus treated has been kept unchanged for a year.