CRKAM RIPENING 241 



life, because they rapidly rusted through from the outside and 

 sprung leaks. Manufacturers of cream vats, therefore, endeav- 

 ored to construct and place on the market, vats of a more dur- 

 able metal and they naturally chose copper for the lining. This 

 step seemed necessary also as the result of the introduction 

 of brine as the cooling medium and its well-known corrosive 

 action on iron. 



Fig*. 36. Enameled cream ripening- tank 

 Courtesy The Pfaudler Co. 



But all efforts, so far, to cover the copper surface with a 

 satisfactory and permanent coating of tin, have been abortive. 

 The exposure of the tinned copper surface of the ripening vat 

 to the sour cream, causes the surface, to soon turn black and 

 the copper to be exposed, jeopardizing the quality of both cream 

 and butter and giving rise to the most disastrous flavor dete- 

 riorations in butter. Hence the copper-lined, tin-coated ripen- 

 ing vats are highly unsatisfactory and their annual retinning 

 involves a very considerable expense. 



Advantages of Glass-Enameled Vats. Because of the gen- 

 eral use in the creamery of brine for cooling the cream it is 

 not feasible to return to the iron-lined, tinned cream ripening 

 vats. But the perfection attained within recent years in the 

 manufacture of glass-enameled vats, now makes possible their 



