286 SCIENCE AND PRACTICE OF DAIRYING. 



If the preparation of condensed milk without the addition of cane 

 sugar is carried on with the necessary precautions, the product obtained 

 is a body possessing great keeping properties, which, when dissolved 

 in a suitable quantity of pure water, yields a liquid possessing all the 

 properties prized in fresh milk, and which indeed leaves little to be 

 desired. Good milk of this sort is manufactured by the manufactory of 

 Drenckhan, in Stendorf, near Eutin, and others. The chemical analyses of 

 several samples of such milk yield the following average compositions: 



Samples from Stendorf. Bremen. 



Water, 66-2 63-8 



Fat, 8-4 9-8 



Nitrogenous matter, ... 10*9 10-4 



Milk-sugar, 12-3 137 



Ash, 2-2 2-3 



100-0 100-0 



The specific gravity of condensed milk of the above composition at 

 15 C. is about 1-1. 



133. Fermented Milk. By inducing alcoholic fermentation in 

 milk by suitable means, it is possible to prepare from it spirituous 

 beverages. Two beverages of this kind are known, viz. kephir and 

 koumiss, which are prepared by the aid of different kinds of fer- 

 ments. In the preparation of these two beverages, it is found that 

 during the alcoholic fermentation, going on at the expense of the 

 milk-sugar, a decomposition of the milk takes place, accompanied 

 with the formation of lactic acid, and the casein separates out in a 

 solid form. Since this decomposition does not exceed certain well- 

 defined limits, and the quantities of lactic acid and alcohol do not 

 exceed a certain amount, the beverages cannot be kept at the 

 ordinary temperatures for any length of time without a certain loss 

 of their beneficial properties; but must be consumed when they are 

 only a few days old. Kephir and koumiss possess a frothy appear- 

 ance, and a taste resembling butter-milk, and contain the casein in 

 the form of a fine suspended coagulum. They are as nutritious as 

 they are easily digested, and exercise, when regularly taken for some 

 time, an excellent dietetic action, which may be ascribed chiefly to 

 the percentage of milk-sugar, alcohol, and carbonic acid they 

 contain. Good kephir should not contain more than 1 per cent of 

 alcohol and lactic acid, and good koumiss not more than at the 

 most 2 per cent of alcohol and 1 per cent of lactic acid. 



