NEUTRALIZATION OF SOUR CREAM 157 



incompletely slaked lime makes an unsatisfactory neutralize!", 

 generally containing much lime carbonate which is coarse, does 

 not strain readily, is insoluble and slow of action in the cream. 



A convenient strength and consistency of milk of lime is 

 secured by two pounds of dry hydrated lime in one gallon of 

 lime mix. In other words, add enough water to two pounds 

 of dry hydrated lime to make up one gallon milk of lime. This 

 formula has the further advantage that it is easily remembered 

 by the operator. Since the preparation of the milk of lime is 

 a somewhat unpleasant operation, it is advisable to. make it 

 up in sufficiently large quantities to avoid having to repeat 

 the operation at too frequent intervals. 



Having adopted this ratio of lime to mix, it is necessary 

 to ascertain how much of this mix it takes to neutralize .01 per 

 cent or .01 pound of lactic acid in 100 pounds of cream. It 

 is necessary here, to remember that the molecular weight of pure 

 lime hydrate is 74, while that of lactic acid is 90, and also that, 

 lime hydrate, being bivalent, its strength is double that of 



lactic acid. In other words, it takes - or 37 pound's of dry 



lime hydrate to neutralize 90 pounds of lactic acid. Hence, 

 the amount of lime hydrate required to neutralize .01 pounds 

 or .01 per cent lactic in 100 pounds of cream is: 



90:37 .01 :X; X .00411 pounds lime hydrate. 



But the lime hydrate is not added to the cream in dry form, 

 but in the form of milk of lime consisting of two pounds of dry 

 hydrated lime in one gallon of mix. Hence it is necessary 

 to know how many pints of this mix are required to neutralize 

 .01 pounds or .01 per cent of lactic acid in 100 pounds of 

 cream. Since the lime mix contains 2 pounds of lime hydrate 

 in one gallon, or in 8 pints of mix, this factor is determined as 

 follows : 



2:8= .00411 : X ; X = .01644 pints lime mix. 



This then means that for every .01 per cent acid in 100 

 pounds of cream that is to be reduced, we must add to the 

 cream .01644 pints of lime mix. 



