CHURNING 289 







The increase of the depression was accompanied by an in- 

 crease of the moisture content of the butter, of the average vol- 

 ume of the fat globules and of the per cent, olein and by a de- 

 crease of the volatile acids and a drop of the melting point. The 

 effect of the decrease of the volatile acids was again off-set and 

 overcome by the marked increase of the per cent, olein. This in 

 turn lowered the melting point 1.1 degrees and yielded the 

 softer butter. The increase in the depression of butter may also 

 have been accelerated by the decided increase of the average size 

 of the fat globules. 



The depression in millimeters indicates the mechanical firm- 

 ness of the butter. The mechanical firmness of butter was deter- 

 mined by measuring the degree of depression under a given 

 weight for a given time. The mechanical firmness is expressed 

 in millimeter depression. 



On the basis of these facts the churning temperature may 

 vary within wide limits, possibly from 42 to 75 degrees F. In 

 the northern and central tier of the dairy belt and under fairly 

 normal conditions the variations of the proper churning tem- 

 perature are confined to within much narrower limits, ranging in 

 summer between about 48 and 53 degrees F. and in winter be- 

 tween about 55 and 60 degrees F. 



In order to use the proper churning temperature it is neces- 

 sary for the buttermaker to familiarize himself with the condi- 

 tions which influence and alter the mechanical firmness of the 

 butterfat he receives, to study the changes of these conditions 

 and the character of the cream as it comes to the factory, and 

 then adjust the churning temperature of his cream accordingly. 

 This is especially important in the spring of the year when the 

 pasture season opens up and in the fall of the year when the 

 cows are stabled. 



The appearance of any conditions which tend to produce 

 firmer fat should be followed by a corresponding rise in the churn- 

 ing temperature and any conditions tending to render the but- 

 terfat softer should be followed by a corresponding drop in the 

 churning temperature. 



Since the firmness of the butterfat directly governs trie 

 time necessary to complete the churning, the buttermaker may 

 use as a convenient guide for the desired temperature of the cream 



