174 NEUTRALIZATION OF SOUR CREAM 



Other Factors That Cause Irregularities of Results of Neu- 

 tralization. The complexity of the physical and chemical 

 make-up of cream, its susceptibility to a variety of changes in 

 composition, which are largely beyond the control of the cream- 

 ery, together with irregularities in the preparation and use of 

 the neutralizer which are largely due to the personal factor of 

 the operator, naturally invite frequent fluctuations in the results 

 of neutralization, and interfere more or less with the desired 

 uniformity and accuracy of the results. Notwithstanding 

 these facts, the use of a systematic process of neutralization 

 makes possible the removal of excess acid and the reduction of 

 the acidity to the desired point, within the limits of not to 

 exceed .05 per cent acid above or below that desired. It en- 

 ables the creamery to secure the full benefit of neutralization 

 without danger of overneutralization and its detrimental effect 

 on the quality of the finished product. 



The dominating factors which cause fluctuations in the re- 

 duction of the acidity of the cream by neutralization are the 

 original per cent acid in the cream before neutralization, the 

 per cent casein in the cream, the amount of carbondioxide in the 

 cream, the strength, dilution and distribution of the lime mix 

 when added, the temperature of the cream and the time allowed 

 for neutralization. 



Effect of Original Per Cent Acid in Cream Before Neutral- 

 ization on Accuracy of Acid Reduction. It has been shown 

 that in the neutralization of cream of average acidity (testing 

 about .60 to .80 per cent acid), a portion of the lime (from about 

 16 to 20 per cent) does not react and that, therefore, lime suffi- 

 cient in amount, or in strength to be equivalent in alkalinity to 16 

 to 20 per cent in excess of that required to theoretically reduce 

 the acidity to the desired point must be added. It was further 

 shown that this loss of reaction of a portion of the lime is due 

 to the fact that a part of the solid particles of lime mechanically 

 combines with the solid particles of casein, rendering the alka- 

 linity of the lime so held inaccessible to the acid in the cream. 



The amount of lime not reacting is, therefore, fairly con- 

 stant and does not vary greatly with the acidity of the cream. 

 It is not proportional with the original per cent acid present 

 in the cream. Hence in very high-acid cream, the 16 to 20 per 



