BUTTER 345 



butter for sale in this country must not contain more 

 than 1 6 per cent, of water. 



The quantity of non-fatty material present varies con- 

 siderably with the kind of cream used, the method of 

 churning, and the amount of kneading or " working " to 

 which the butter has been subjected, with the object of 

 removing buttermilk. In most dairies a small quantity 

 of salt is also added. 



The following may be taken as the average composi- 

 tion of fresh and salt butter respectively : 



Fresh Butter. Salt Butter. 



Water . . .14 12.5 



Fat . ... , 83.5 84.5 



Protein .... .8 .5 



Milk-sugar . . .1.5 .6 



Ash ... . .2 .1 



Salt ". * : ... 1.8 



Butter is composed of eight or more distinct kinds of 

 fats, which are of course present also in normal milk. 

 The chief of these are the fats palmitin, stearin, and 

 olein, glycerides of palmitic, stearic, and oleic acids 

 respectively, and butyrin t caproin, caprylin, caprin, 

 and myrtstin, glycerides of butyric, caproic, caprylic, 

 capric, and myristic acids. 



The last five acids are soluble in water, and are known 

 as volatile fatty acids, since they can be distilled over in 

 a current of steam without change : the first three are 

 insoluble and non-volatile. 



Palmitin and stearin are solid white compounds, which 

 occur also in beef and mutton fats ; olein is a liquid fat 

 which only solidifies at or below about 40 F. ; it is found 



