134 SAMPLING MILK AND CREAM 



from which it is taken. This in turn results in a low overrun 

 and loss to the creamery. Cans in which the cream is com- 

 pletely frozen cannot be sampled at all without first thawing 

 the cream. 



In order to reduce the frozen cream to a liquid condition 

 most creameries use a wooden, concrete or iron' tank partly 

 filled with warm water, into which they set the cans of frozen 

 cream until the cream is melted. The operators are usually 

 instructed to hold the temperature of the water at 110 to 130 

 degrees F. In order to hasten the work and to avoid delay 

 there is always a strong temptation on the part of the operator 

 to use too hot water or to pull the cans out of the thawing tank 

 before all the cream is melted. Both of these practices are 

 objectionable, because they are prone to yield incorrect sam- 

 ples and they tend to injure the body of the resulting butter. 



If too hot water is used, at least a part of the cream is 

 bound to be heated much above the melting point of the but- 

 terfat. This causes the fat to "oil off" and run together. When 

 this cream is subsequently cooled, preparatory to churning, this 

 "oiled-off" fat granulates and gives the butter a disagreeable, 

 mealy texture. In this "oiled-off" condition the cream is also 

 very difficult to sample because, in spite of most thorough stir- 

 ring, the butter oil will rise to the top before the operation 

 of sampling is finished and the sample is very apt to contain 

 a higher per cent of fat than the mixed cream from which it is 

 taken. 



If the cans are pulled out of the hot water tank before all 

 the cream is properly melted, much vigorous stirring is neces- 

 sary in order to reduce it to a homogeneous condition. In the 

 case of sour cream this stirring of the partly melted cream is 

 often sufficient to cause the butter to break, when proper sam- 

 pling becomes impossible and the remelting of this churned 

 cream in the forewarmer or pasteurizer again gives rise to but- 

 ter with a mealy texture. 



The only reliable way of avoiding these difficulties is to 

 not heat the water to high enough a temperature to cause the 

 butterfat to melt and "oil-off" and to leave the cans in the water 

 long enough to insure complete solution of the cream. This 

 is best done by heating the water in the tank to 95 degrees F. 



