64 MILK PRODUCTS. 



Butter containing over forty per cent, of water, has been 

 sold in this city. Such samples are pale and spongy, 

 lose weight and become rancid very rapidly. 



It is generally considered that butter should not con- 

 tain more than i6 per cent, water. An excess of water 

 diminishes the keeping quality. 



The following methods for the analysis of butter 

 have been adopted by the Association of Official Ag- 

 ricultural Chemists: — 



"Sampling. — If large quantities of butter are to be 

 sampled, a butter, trier or sampler may be used. The 

 portions drawn, about 500 grams, are to be carefully 

 melted in a closed vessel, at as low a heat as possible, 

 and when melted the whole is to be shaken violently 

 for some minutes till homogeneous. The mass must be 

 sufficiently solidified to prevent the separation of the 

 water and fat. A portion is then placed in the vessel 

 from which it is to be weighed for analysis, and should 

 nearly or quite fill it. It should be kept in a cold place 

 until analyzed. Determinations are made as follows : — 



Water. — 1.5-2.5 grams are dried to constant weight 

 at the temperature of boiling water in a dish with a flat 

 bottom, having a surface of at least 20 sq. cm. 



Fat. — The dry butter from the water determination 

 is dissolved in the dish with absolute ether, or with 76° 

 benzin. The contents of the dish are then transferred 

 to a Gooch crucible with the aid of a wash-bottle filled 

 with the solvent, and are washed until free from fat. 

 The crucible and contents are dried at the temperature 



