CREAM RIPENING 221 



in a good starter have the greatest relative growth at 70 F., or a 

 little above. Generally speaking, it is advisable to adopt a little 

 lower ripening temperature in summer than in winter. For one 

 thing, the cream has a tendency to rise a little in temperature in 

 summer and to fall a little in winter, during the time of ripening; 

 and furthermore, the natural bacterial flora present in summer are 

 more favorable to cream-ripening than those present in winter. 

 With the necessary modifications to meet conditions, 65 to 70 

 will be found a suitable range of temperature to adopt during the 

 summer season and 70 to 74 during the fall and winter months. 

 The amount of starter used and the length of the ripening period 

 are factors that must be considered in deciding upon the tem- 

 perature to be used. Where a fairly high ripening temperature 

 is adopted a little greater precaution must be taken to prevent 

 over-ripening of the cream, particularly if a liberal amount ot a 

 good, active starter be used. 



Amount of Starter to Add to Cream. The amount of starter 

 to add, the ripening temperature and the length of the ripening 

 period are related factors that influence each other. Also the 

 richness of the cream places a limit upon the amount of starter 

 that can be used. Generally speaking, where the separating is 

 done on the farm the richness of a vat of cream is not so great as 

 where the milk is delivered to and separated at the creamery, 

 and consequently it is not practicable to use so high a per cent 

 of starter in the former as in the latter case. The quantity of 

 starter used will range from ic to 20 per cent, depending upon the 

 ripening temperature adopted, the richness of the cream, the time 

 within which the ripening is to be done, and, to some extent, the 

 cost of the milk or skim-milk used in making the starter. 



Mixing the Starter with the Cream. When the starter is 

 added to a vat of cream the coils should be run for a few 

 minutes in order to mix the two very thoroughly. This is 

 necessary to insure uniformity of ripening. 



Tests for Acidity. The acid in cream is developed in the milk- 

 serum, and the per cent of butter-fat that cream contains merely 

 takes up space. Hence, in ripening cream some consideration 

 should be given to the per cent of fat in it, as the fat is a neutral 



