BUTTER DEFECTS 493 



salts the action is relatively slight. Nickel and tin are practi- 

 cally negative in this respect and do not produce tallowy flavor 

 in butter. 



Most of the equipment used in the handling of cream and 

 the manufacture of butter is constructed of iron or copper, usu- 

 ally originally coated with tin. When this tin coating wears' 

 off, as it always does to a greater or less extent, the iron or 

 copper becomes exposed, and often the exposed iron is permitted 

 to rust and the exposed copper allowed to become coated with 

 verdigris. In this condition, these metals are most active, con- 

 siderable portions being dissolved by the acid in the cream and 

 thereby not only act in the cream, but also find their way into 

 the butter, jeopardizing its quality and inviting the development 

 of tallowy flavor. 



This danger can best be minimized, if not entirely avoided, 

 by furnishing the farmer with bright and non-rusty cans and 

 by preventing the cans from rusting, by systematic and thor- 

 ough washing, rinsing, steaming and drying; keeping weigh 

 cans, forewarmers, pasteurizers, coolers, pumps and pipes and 

 conduits well tinned, thoroughly cleaning and steaming them 

 after each day's use and flushing them with hot water each 

 morning- before circulating the cream, so as to remove any 

 remnants of water of the previous day which may be pregnant 

 with metallic salts; removing the rust from all parts of the 

 packing and printing equipment and using wrappers and liners 

 only which are free from metallic specks. Water used for 

 washing butter should be free, or nearly so, from iron. 



4. Presence in Butter of Excess Lactose. The presence in 

 butter, in excess, of specific compounds which are themselves 

 readily oxidized may yield tallowy flavor, as one of their oxida- 

 tion products. To these compounds belong lactose, glucose and 

 glycerol. Danger from these products need be considered only, 

 however, when the cream or butter is subjected to alkaline con- 

 dition, as shown in the succeeding paragraph. When butter 

 is made under proper conditions, and containing a normal 

 amount of acid, the presence of lactose and similar compounds 

 has no injurious effect on its flavor and does not, in itself, con- 

 stitute a cause of tallowy butter. In fact, the addition of lac- 



