American Cheddar. Factory System 



With pepsin as the coagulant it is necessary to ripen the milk 

 somewhat further than if rennet is used, in fact to the danger-point 

 where a little more acidity is apt to do harm and produce a dry and 

 trumhly cheese and loss of butter-fat in the whey. Most cheese 

 makers therefore prefer rennet when they can get it. 



The rennet having been added, the 

 milk is left undisturbed until a firm 

 curd has been formed. When the curd 

 breaks or splits sharply before the 

 finger pushed slowly through it, it is 

 ready to be "cut." 



Cutting. Two sets of curd knives 

 are used, each consisting of a metal 

 frame in which tinned steel blades are 

 hung, in one vertically and in the other 

 horizontally. The vertical knife is 

 first carried slowlv through the curd 

 lengthwise and crosswise; the horizon- 

 tal set of blades is then moved care- 

 fully through the length of the vat. 

 Wlien the cutting is over, the entire 

 mass should be in cubes about half an 

 Curd Knives inch Square. 



The whey that begins to separate out should be clear and yellow. 

 Milky whey is a sign that the butterfat is escaping in it; the curd 

 has been broken up too violently. In curdling, the casein encases 

 the butter-fat and the object of the breaking up of the curd in the 

 vat is to expel the whey but retain the fat in the cheese. 



"Cooking" the Curd. Gentle heat is now applied to raise the 

 temperature gradually to 98° or 100° in the course of about .30 

 minutes. Meanwhile the small pieces of curd are kept floating in 

 the whey by gentle stirring with a rake and the hands, and are not 

 allowed to pack at the bottom of the vat. The heating is easily 



The ferment acts best when the milk is lul<ewarm, but it will do the work 

 at temperatures ranging from fM", or even lower, to 120° F. Strongly pas- 

 teurized or sterilized milk will not curdle with rennet, hut milk pasteurized at 

 a low temperature is not changed enough to prevent it from making a firm curd. 

 More rennet does not make a firmer curd but causes the milk to curdle quicker ; 

 less rennet makes the process slower. Diluted milk will not curdle firmly, and 

 the failure o( milk to make a smooth eoagulum of the usual consistency and In 

 the usual time, the temperature being right and the regular amount of a 

 standard lennet being used, is a never-failing proof that something is the 

 matter with the milk. It has been changed from its natural condition by over- 

 heating in pasteurization or by watering or doctoring, or it has not been 

 properly ripened. 



