CA′SEIN. Syn. Ca′seum, Ca′sein, Lactalbu′men, Albumen of milk. The nitrogenous principle of milk. Cheese made from skimmed milk and well pressed is nearly pure casein. (Liebig.)
Prep. 1. The curd obtained by adding dilute sulphuric acid to milk is well washed and dissolved in carbonate of soda. It is allowed to stand for 24 hours, to let the oil rise to the surface, and when this is properly skimmed off, the casein is precipitated by an acid. The process is repeated a second time, and the coagulum digested with alcohol and ether, and dried. With all these precautions the casein still contains some saline matter which cannot be removed.
2. Milk is coagulated by hydrochloric acid, and the curd then well washed with dilute acid, and finally with pure water. The curd so prepared is dissolved by digestion at 110° Fahr., with a large quantity of water; the solution, after filtration, is coagulated with carbonate of ammonia; the coagulum is washed with water, ether, and alcohol, and finally dried.
Prop., &c. Coagulated casein is readily dissolved by the alkalies and alkaline carbonates. The most remarkable property of casein is its coagulation by certain animal membranes, as in the process of cheese-making with rennet. See Lactarin.
CASKS. The care and management of casks is an important affair in a large establishment. It is found that they last longest when stored either in a dry situation, or in one uniformly very moist. Continual variations from the one to the other speedily rot them. As soon as casks are emptied they should be bunged down quite air-tight, with as much care as if they were full, by which means they will be preserved both sweet and sound. Should any of the hoops become loose they should be immediately driven up tight, which will at once prevent the liability of their being lost or misplaced, as well as the casks fouling or becoming musty from the admission of air. For this purpose those out of use should be occasionally hauled over and examined.
Numerous plans are adopted for CLEANING and PURIFYING CASKS, among which are the following:—
1. Wash them well out with oil of vitriol, diluted with an equal weight of water.
2. Wash them first with a little chloride of lime and warm water, and then with water soured with oil of vitriol.
3. Match them with sulphur, or with sulphur mixed with a little saltpetre.
4. Unhead them and whitewash them with fresh milk of lime, made pretty strong. This plan is commonly followed for brewers’ vats.