CHAP. VIII. USE OF ICE IN BUTTER FACTORIES. 861 



height of the milk in the pails that is the level of each should be 

 coincident. The cream in this arrangement, as it rises, is kept cool ; 

 but in the winter season the level of the surface of milk in the pails 

 should be above that of the water in the vat by some inches. The 

 proportion of the ice used in cooling the water to the milk to be cooled 

 varies, but on an average the quantities of each are about equal. By 

 careful management the ice has been reduced to one-third ; thus, in 

 the Central Company at Stockholm, 1,500 cwt. of ice were used to 

 cool the milk necessary to produce 2,500 cwt. of butter. 



On the milk being delivered at the receiving houses, it is measured, 

 and a small sample put into a graduated glass cylinder, which is left 

 for cream setting, so that an idea may be obtained of its quality. The 

 milk is then strained into the pails, and these are placed in the vats 

 with about three inches interval between them. The temperature of 

 the milk-room the ice-water in the vats, and that of the milk itself 

 deciding the rising of the cream, the time taken by the latter varies. 

 On an average the milk will be ready for skimming in about 10 to 

 12 hours, with a temperature of 35 of the ice- water, but more and 

 better cream is got by allowing it to stand for 18 or 24 hours. The 

 temperature of the milk-room should be as low as possible in summer, 

 never below 50 in winter. The sooner the cream is churned the 

 better, is the experience of the Swedish factories or, as their reporter 

 puts it, " the fresher and absolutely sweeter the cream is, the better 

 will the butter be." As we have seen from experience in this country, 

 opinion differs on this. On arrival at the factory the cream is put into 

 the ice-water vats at once to keep it cool and sweet. The average 

 results of working may be stated thus : 2'65 gallons of milk yield 0*44, 

 or nearly half a gallon of cream ; this churned gives 0'93, or nearly 

 one English pound of butter. The temperature of the cream found 

 best for churning varies with the quality of the cream, the temperature 

 of the churning-room, &c. There is one great advantage obtained by 

 using iced-water in place of cold well-water even if that can be obtained 

 at a temperature sufficiently low, and this is that while the well-water 

 in the cooling vats requires to be constantly changed, the ice-water 

 need not be changed oftener than a few times in the year. The surplus 

 water from the melting of the ice is carried off by a small pipe, the 

 orifice of which is near the upper edge of the vat. 



The ice is not stored in a regularly-built house, but simply heaped 

 up in a pyramidal form, in the open air generally, but sometimes in a 

 shed, and covered with saw-dust, tanners' bark, or other good non- 

 conducting material. Great care is taken to keep down the number 

 and size of the spaces or interstices between the blocks of ice, and 

 these where they exist are carefully filled up with sawdust. When ice 

 is removed from the heap it is taken from the top, working downwards, 

 and the spaces made by the removal are carefully filled up with saw- 

 dust. The lowest layer, or the bottom blocks, rest upon a layer of the 

 non-conducting material at least a foot in depth. 



The dairy factory system has made remarkable strides in Denmark, 

 a circumstance that is chiefly due to the fact that a ready market was 



