162 



NEUTRALIZATION OF SOUR CREAM 



Table 26. Reduction of Per Cent Acid in Cream and in Aqueous 

 Solution of Lactic Acid and Per cent of Lime not Reacting. 



Enough lime was added in each case to theoretically reduce the 



acidity to .25%. 



From the above tables, it is evident that from about 16 to 

 20 per cent of the theoretically correct amount of lime added, 

 fails to react with the lactic acid of the cream. In the factory 

 tests the lime not so reacting averaged 16.3 per cent of the 

 total lime added, while in the laboratory tests the deficiency 

 in acid reduction averaged the equivalent of 19.6 per cent of 

 the lime added. In the laboratory tests the amount of cream 

 used was relatively very small and the preparation of the cor- 

 respondingly very small amount of lime mix needed was diffi- 

 cult, obviously inviting relatively large experimental errors. It 

 may be assumed, therefore, with reasonable certainty that for 

 all practical purposes about 16 per cent of the theoretically cal- 

 culated amount of lime that is required to neutralize the acidity 

 in cream to .25 per cent fails to react on the lactic acid. 



In order, therefore, to secure the full neutralizing action 

 desired, that is to -reduce the acidity of the cream to 

 .25 per cent by the use of the neutralizing formula and tables 

 given, it is necessary to increase the neutralizing strength of 

 the milk of lime at least 16 per cent. This can readily be done 

 in one or the other of the following ways : 



a) By using a correspondingly larger proportion of dry 

 hydrated lime in making up the lime mix. Since the acid- 

 reducing power of the lime mix is approximately 16 per cent 

 less than the theoretical calculations specify, each 100 parts 

 of lime mix has an actual neutralizing strength of only 84 parts. 



