MILK AND ITS PRODUCTS 173 



acidity of .4% or more, the ripening may be finished at a 

 temperature between 55 and 60 with good results. In 

 general practice a temperature between 60 and 70 gives 

 the best results. This means that the main portion of the 

 ripening is done at this temperature. The ripening is 

 always finished at temperatures lower than this. 



Time in Ripening. As a rule quick ripening gives 

 better results than slow. The reason for this is evident. 

 Quick ripening means a rapid development of the lactic 

 fermentation and, therefore, a relatively slow develop- 

 ment of other fermentations. Practical experience shows 

 us that the growth of the undesirable germs is slow in 

 proportion as that of the lactic is rapid. For instance, 

 when we attempt to ripen cream at 55 F., a tempera- 

 ture unfavorable for the growth of the lactic acid bac- 

 teria, a more or less bitter flavor is always the result. 

 This is so because the bitter germs develop better at low 

 temperatures than the lactic acid bacteria. 



Stirring Cream. It is very essential in cream ripen- 

 ing to agitate the cream frequently to insure uniform 

 ripening. When cream remains undisturbed for some 

 time the fat rises in the same way that it does in milk, 

 though in a less marked degree. The result is that the 

 upper layers are richer than the lower and will sour less 

 rapidly, since the action of the lactic acid germs is 

 greater in thin than in rich cream. 



This uneven ripening leads to a poor bodied cream. 

 Instead of being smooth and glossy, it will appear coarse 

 and curdy when poured from a dipper. The importance 

 of stirring frequently during ripening should therefore 

 not be underestimated. 



The Use of Sour Milk (Starter). Cream produced 

 under cleanly conditions ordinarily contains many kinds 



