406 MANUAL OF MILK PRODUCTS 



for by this time there is a very large army of bacteria at work. 

 On Wednesday morning churn the 40 lb. of cream and start 

 the ripening process anew with Wednesday's cream. 



It is important not to develop too much acid. The amount 

 of inoculation and the temperature must be managed so as to 

 gain a certain end under certain conditions. 

 Methods of determining the ripeness of cream. 



It is important that the ripening process should be carefully 

 controlled, and that the cream should have the proper degree 

 of ripeness before it is churned. The ripening is caused by the 

 development of lactic acid as a result of the action of the lactic 

 bacteria and the amount of acid development will determine 

 to a large extent the flavor and aroma of the butter. The 

 commonest method for determining the ripeness of the cream 

 on the farm is by its taste and smell. It should have a clean 

 acid flavor without any objectionable flavor. The degree of 

 ripeness may also be judged by the appearance. When the 

 cream is well ripened, it becomes slightly thickened and takes 

 on a more or less glossy appearance. Another method for 

 determining the degree of ripeness is to make an acid test, as is 

 done in regular creamery practice. This test is made by 

 treating a definite amount of the cream with an alkaline solu- 

 tion and an indicator. The cream is measured out into a 

 white cup and the indicator added, after which the alkaline 

 solution is slowly run into the cream while it is being stirred. 

 The appearance of a faint pink tint indicates the point at 

 which the acid in the cream is neutralized by the alkaline 

 solution. The amount of acid present is then calculated 

 from the amount of alkaline solution used. Several methods 

 for making this test are in common use and the apparatus 

 and directions can be secured from the different dairy supply 

 houses. Either Farrington's alkaline tablets (p. 134) or Pub- 

 low's acid test (p. 300) will give satisfactory results and is 

 easy to use. In many cases, this method of determining the 



