RENOVATED BUTTER 585 



upward through the melted butter oil. The butter oil is kept in 

 melted condition by the passage of hot water through the jacket 

 of the purifying tank. It is aimed to maintain a temperature of 

 approximately 110 degrees F. This aeration is continued until 

 the liquid fat has became "Neutral," that is until apparently all 

 foreign odor and free acids have been blown out of it. 



Addition of Starter. This butter oil is now without flavor. 

 In order to return to it, the characteristic butter flavor, starter 

 made from skimmilk or whole milk is added. Lactic acid cul- 

 tures, the same as are used in cream ripening, are employed for 

 making this starter, care being taken that the starter does not 

 become overripe, in which case there would be danger of 

 impregnating the finished renovated butter with white specks. 

 The amount of starter used varies greatly, ranging from about 

 two per cent to fifty per cent. The starter is thoroughly mixed 

 with the butter oil, either in the blower tanks or in special tanks 

 equipped with mechanical agitators. 



Coloring. It is usually not necessary to add color to the 

 mixture. Most of the dairy butter surplus is made during the 

 summer season, when butterfat has naturally a high color. In 

 case the butter oil is deficient in natural color, a sufficient amount 

 of artificial coloring matter is added to suit the market. 



Crystallizing. The emulsion of butter oil and starter is 

 plunged, in the form of a fine stream, into ice water, or water 

 cooled by artificial refrigeration, to a few degrees above the 

 freezing point. This sudden chilling immediately crystallizes 

 the fat, precipitating it in the form of flakes. The crystallizing is 

 accomplished in long vats filled with cold water. The end of the 

 vat that receives the liquid butter oil 'is equipped with a revolv- 

 ing paddle wheel. The fat drips down into the water slowly, 

 as soon as it strikes the water it solidifies in the form of flakes. 

 The revolving paddle wheel starts these flakes toward the op- 

 posite end of the vat, so that the thin stream of melted fat 

 always strikes the cold water direct and does not pile up on the 

 flakes already formed. 



In the case the cooling is done in ice water, instead of 

 in water kept cold by artificial refrigeration, cakes of ice are 

 usually anchored in the bottom of the vat, so as to avoid warm- 

 ing up of the water. 



