510 MANUAL OF MILK PRODUCTS 



(1) Propagate a small culture from day to day as indicated 

 in the directions given above. 



(2) Carry in a similar way a culture of the ordinary sour- 

 milk organism, which may be obtained from many of the 

 commercial laboratories. 



(3) Thoroughly pasteurize the milk to be fermented. If a 

 small quantity — 5 to 10 gallons, for instance — is to be made, 

 it may be done by holding a can of milk in a tub or vat of water 

 heated by a steam hose. If a larger quantity is made, one of 

 the starter cans used in creameries will be found convenient. 

 These are essentially cylindrical vats with mechanical stirrers 

 and a jacket which can be filled with steam for heating or water 

 for cooling. The milk should be held at a temperature of at 

 least 180° F. for not less than thirty minutes. 



(4) Cool the milk to about 100° F. Draw off one-half and 

 inoculate it with the culture obtained in (2). Inoculate the 

 remaining half with the bulgaricus culture obtained in (1). 

 The amount to be added will depend on the quantity of milk 

 to be fermented, the time at which it is desired to have it 

 curdled, and the temperature maintained during the fermen- 

 tation. This can best be determined by experience. One 

 pint should be sufficient for any amount between 10 and 20 

 gallons. 



(5) The milk inoculated with (2) may be held at ordinary 

 room temperature. Precautions must be taken to hold that 

 part inoculated with the bulgaricus culture at a temperature of 

 90° to 100° F. for several hours. If the milk is in cans, it may 

 be set in a tub of warm water. A large volume of milk in a 

 warm room will maintain the proper temperature. 



If one is unable to hold the milk at the desired temperature, 

 the amount of culture inoculation should be increased. 



(6) When the milk has curdled, which should be in ten or 

 twelve hours, mix the two lots thoroughly by churning or stir- 

 ring together, bottle, and put on ice to check the acid formation. 



