CURD-MAKING 73 



top to bottom for about three to four minutes. For 

 this purpose, either a long-handled dipper or a wooden 

 rake may be used. A dipperful should be drawn from 

 the gate and stirred into the vat, otherwise the milk in 

 the gate will fail to coagulate properly because the rennet 

 diffuses too slowly to reach and affect all the milk at that 

 point. The milk should be stirred on the top, preferably 

 with the bottom of a dipper, until signs of coagulation 

 begin to appear. This stirring keeps the cream from 

 rising. There are various ways or signs to indicate 

 when the coagulation has gone to the stage at which 

 the mix is about to become thick : (1) The milk becomes 

 lazy or thicker as the finger is passed through it; (2) 

 bubbles caused by moving the finger remain on the milk 

 longer, usually until one can count ten when ready to 

 thicken. 



If the milk is stirred too long or after it begins to thicken, 

 the result is a granular sort of curd, and there will be an 

 abnormally large loss of fat in the manufacturing process. 

 The addition of the rennet and subsequent stirring re- 

 quire the exercise of great care and constant attention to 

 details. The cheese-maker can do nothing else for those 

 few minutes. When through stirring, it is a good plan 

 in cold weather to cover the vat with a cloth as this will 

 keep the surface of the curd warm. In summer the same 

 cover will keep out the flies. 



Causes of a delayed coagulation : 



(1) Weak rennet extract or too small an amount. 



(2) Low temperatures due to inaccurate thermometers. 



(3) Pasteurized milk. 



(4) Presence of abnormal bacterial ferments. 



(5) Presence of preservatives. 



