BUTTER-MAKING. 788 BUTTER-TREE. shallow setting in creameries and in large dairies during the past few years. In this method the cream is separated from the milk by centrifugal force, in a bowl or drum, revolving at a high rate of speed, from .iOOO to 8000 revolutions a minute and even more. The milk enters through a tube reaching to the centre and near the bot- tom of the bowl, where the high rate of speed causes the heavier milk tluid (the serum) to gravitate toward the circumference of the bowl, while the lighter cream remains near the centre and rises to the upper part of the bowl. The skim milk Hows out through a side tube, and the cream through a second tube leading from the centre near the top. The operaticm is continuous, milk flowing into the bowl and .^kim milk and cream ilowing out of it without interruption. The rate of separation varies with the size and capacity of the machine, the smaller hand sejia- rators skimming from 200 to .'jOO pounds an hour, and the larger fonns 2000 pounds and over. By means of various appliances within the bowl the separation of the fat is made quite complete, the skim milk from a good separator properly operated containing only about 0.1 per cent, of fat and in some cases only 0.05 per cent. The cream obtained by setting or by the separator may be churned at once, as is the case in making sweet-ercam butter, or may be first 'ripened' or soured. The object in ripening is to develop the characteristic flavors of butter and a slight acidity which aids in churning and affects the texture' of the butter. Eipening is elTected by adding to the cream a 'starter' of sour skim milk, buttermilk, or cream from a preceding churning, or a commercial preparation of the desired micro-organisms called a lactic femient or pure culture. It is necessary to prevent ac- cess to the cream of any germs which may cause im|)roper souring, or impart an undesirable taste or qualit.v to the butter, and it is with this view that pure cultures are used for ripening. Pasteurization of the milk or cream used in butter-making, which is practiced quite exten- sively in some countries, has the same object, the tlieory being to kill all the germs which may he in the milk or cream, and add only such as are desirable. The cream is ripened with the aid of the starter mentioned, by keeping it at a constant temperature (00° to" 70" F.) until the proper amomt of aeid has developed, the time required dei)ending upon the number of germs present and upon the temi)erature. It is then ready for churning. In this process the cream is agitated in a churn (([.v.) to cause the particles of biitter fat to iite into masses so that they can he separated from the buttermilk. This is ac- conqilished at a temperature of from 30° to Go" ]., the larger fat-gloliulos congealing and uniting first, and the smaller ones adhering to these as they come in contact with them. Finally the whole body of fat may be brought tog<'ther in a practically solid mass and the buttermilk di'ained off. .fter washing, the butter is worked by hand or by machine (see Bitter-Worker) to remove the buttermilk and washings more completely, is salted to suit the taste, and ttien is either packed in tubs or boxes, or made into |)rints. Various factors affect the quality of butter aside from the care in making, .mong these are the feed of the cows, the conditions under which they are kept, the stage of lactation of the cows, the handling of the milk and cream to avoid ab- sorbing odors or becoming tainted, etc. The per- fection of the sei)arator aiul other dairy machin- ery has led to material improvement in the quality of American butter, and has made it possible to make good butter in almost all parts of the United States. Scrupulous cleanliness and close attention to every detail, from the produc- tion of the milk to the tinal packing of the finished product, are i>rime requisites to suc- cess. Since the introduction of the creamery system the amount of butter made on farms h.aa greatly decreased, but there is still much more butter made on farms than in creameries, al- though creamery butter controls all the large- markets. See, also. Creameries and D.tryijig. Fur more detailed accoimts of the processes of Imtter-making, the i-eader is referred to H. H. Wing. MUk and Its Products (New York, ISnO) ; ••IJutler-iiaking on the Farm," United Stales Department of Agriculture, Farmers' Bulletin, No. .57 (Washington, ISilit) ; and Handbook of Experiment Station Worh, also issued by the United States Department of Agriculture.' BUTTERMILK. The liquid remaining after till' liutter fat has been separated from cream by churning. It consists largely of the water, sugar, casein, and ash of the cream, together v.itli a small amount of lactic acid produced in the ripening of the cream (see Bltter-M.vkixg),. which gives it a slightly acid taste. It also con- tains a small amount of fat. depending vipon the completeness of churning, which failed to sepa- rate from the serum. Its composition varies, but is approximately as follows: Water. 91; casein, 3; milk sugar, 4.8; fat, 0.5; and ash, 0.7 per cetit. It is a healthful and nutritious beverage, much relished by some j)ersons. In many localities it is used to a considerable ex- tent for feeding pigs, corn-meal or some other grain being usually added to it. For this pur- pose it has been found to be nearly equal to skim milk, which contains about one-fifth more solid constituents. The pork produced upon it is of excellent quality. See BLTTER-ilAKi>>G. BUTTERNUT (so called on account of its oil), or White Walxit IJur/lans ciiieren). A large, wide-spreading American tree 50 to 75 feet high, ranging from Xew England to Georgia, and west to ilinnesota and Kansas, with nearly smooth bark, and large comiimmd leaves. The leaves and green nuts are clanuuy and pubescent. The nuts are well known, and form agreeable food when dried: when taken green and pickled they are prized for the table. The nuts contain as much as 4 per cent, of fixed oil, which is sometimes extracted or expressed. Sugar can be made from the sap, but it is much inferior to that made from the maple. The timber is useful for coach and cabinet work, posts, rails, and wooden bowls. The bark of the root is mildly cathartic. . dyeslutr was formerly prepare<l from the bark and husks, and was quite widely used at one time for dyeing woolens, etc., a light reddish brown. For additional illustration, see riate of Brazilnut. See Walxi't. BUTTER, KocK. See Rock Bitter. BUTTER-TREE. . name given to several trojiical trees, of different orders, the fruit of which yield complex fi.xed oils, having somewhat the appearance, and used for the purpose, of butter. The butter-trees of Ijidia and .Vfrica
