212 SCIENCE AND PRACTICE OF DAIRYING. 



In the separation of milk, in addition to the necessary quantity of 

 good rennet, and a good cheese-vat and suitable measuring vessels, a 

 thermometer and a ladle for mixing the rennet with the milk will also be 

 required. The following is the method : After the milk has been brought 

 by suitable heating and stirring to exactly the required temperature, the 

 necessary amount of rennet is mixed into the milk. If it be intended to 

 colour the coagulum of the cheese, the colouring matter ought also to be 

 added in the exact proportion required, and should be thoroughly mixed 

 with the milk. The milk is then allowed to rest in the cheese-vat covered 

 with a lid, should it be necessary to maintain an equable temperature, and 

 the liquid left to stand. The solution of rennet (rennet in the form of 

 a powder must be dissolved before application) should form at least 1 per 

 cent of the volume of the milk. The milk is tested from time to time, at 

 first after considerable intervals, and subsequently oftener, in order to see 

 if coagulation have taken place. Before proceeding further, the coagulum 

 must be allowed to attain the desired degree of firmness. As soon as 

 this is reached, it is ready for further treatment, in the cheese-vat, for the 

 manufacture of cheese. 



For taking the temperature during the process of coagulation, a ther- 

 mometer fitted with a brass scale attached to a strong board, polished on 

 all sides, is used. The necessary rennet is kept (when a rennet solution is 

 used) protected from the action of light, and if a rennet powder be used it 

 should be kept in a perfectly dry place. 



If it be desired to test the rennet solution which is used, it can be done 

 in the following manner: The entire quantity of the milk is brought into 

 the cheese vessel at the proper temperature. An empty dish, which will 

 hold at least two litres, is placed in the milk at the beginning of the 

 warming process, in such a way that it floats and assumes the temperature 

 of the milk. In the meantime 10 c.c. of the rennet solution are measured 

 out and diluted with water to 100 c.c. As soon as the mass in the vessel 

 has reached the desired temperature, a litre of milk is poured into the 

 dish, 10 c.c. of the diluted rennet solution is added and mixed, and the 

 time which it takes to start coagulation is noted exactly to a second. If, 

 for example, it has been observed that the milk in the bowl coagulates in 

 8-5 minutes, and if it be desired that the coagulation of the whole amount 

 should last for about 40 minutes, all that is necessary is to divide 8-5 by 

 40 in order to find how many c.c. of rennet will be required for every litre 

 of milk. Since 8-5 divided by 40 is -2125, for every litre "21 c.c. will be 

 required approximately, or for every 100 litres 21 c.c.; arid since a litre 

 weighs approximately 2 Ibs., for every 100 Ibs., 10'5 c.c. of rennet will 

 be required. It is possible at the same time to ascertain whether the 

 coagulum possesses the proper condition, by making an exact test of the 



