526 Journal of Agriculture. [9 Sept., 1907. 



Reverting to our trials. I found that cream of an aciditv up to .35, 

 if sound, could be manufactured into choicest butter. Cream up to .45, 

 allowing for a reduction in acidity, could be made into a good keeping 

 and carrying butter, or, to put it more plainly, I am of opinion that all 

 93. butter can be made superfine, and a large proportion of our 92. butter 

 can also be made superfine, provided efficient pasteurisation and pure 

 cultures are used. 



The plant required for pasteurising is simply a heater, but pasteuri- 

 sation must be followed by quick cooling. We must remember that im- 

 proper pasteurisation is worse than no pasteurisation, and pasteurisation 

 withO'Ut proper cooling is just as bad. In treating cream at various acidi- 

 ties, I believe that 160 to 165 degrees F., is the best temperature at which 

 to run cream under .35 acidity, and for cream over this aciditv a tempera- 

 ture of 170 to 175 degrees F. You will find that with this latter temperature 

 there will be very little danger of coagulation in the pasteuriser. A cream 

 which will go stringy or coagulate at 145 to 150 degrees will be found to go 

 through easily at the higher temperature, and that is the main difficultv in 

 pasteurising home separator supplv. This particular aspect of the question 

 should not be lost sight of. 



When we have decided to pasteurise, we must also decide to use pure 

 cultures ; they necessarily go together, and the making of a pure starter is, 

 under ordinary circumstances, the most difficult thing in the svstem. In 

 the preparation of starters it is expedient to use either a commercial culture, 

 or one received from some reliable source, such as the University Labora- 

 tory. The small bottle received is first of all propagated in two gallons 

 of skim milk which has been pasteurised for an hour in the water tank 

 at from 170 to 180 degrees F., and cooled to 90 degrees F. This is allowed 

 to stand from 14 to 16 hours at a fairly even temperature when it 

 will be found coagulated. Of course sterilised vessels must be used, and 

 kept covered with clean butter cloth. When the starter is coagulated, it 

 nmst be skimmed, thoroughly broken up and then added to, say, 20 gallons 

 cf pasteurised skim milk cooled to 90 degrees, which, on the following 

 day is ready for use in cream. Suflficient should be kept over from day to 

 day to propagate enough pasteurised skim milk for use each succeeding 

 day. The starter should be always of smooth texture, not lumpv, and 

 should not be used if showing whey. If proper care is taken a starter 

 may be used for as long as three months, and if it lasts six weeks it is 

 evidence of good work. The quantitv of starter must be reigulated by the 

 temperature, length of time of ripening, &c. Personallv, I would cool 

 in the vicinity of 60 degrees F., and 8 per cent, starter, and have ready 

 Tor churning in 14 to 16 hours, at a temperature of 56 degrees F. 



Coming to the cost of the system. I would like to have the experience 

 of those managers who have' been practising the .method. There is the 

 extra labour, heating and cooling. I have been given to understand that 

 cne horse plant is sufficient for heating 300 gallons per hour and driving 

 the necessarv machinery. I have found it impossible in mv experiments 

 to arrive at the cost of heating. Storch, in working it out, puts it at one-fifth 

 of a farthing iper lb. of butter when milk is treated. Where there is plenty 

 of water available, the cost of cooling is practicallv nothing. I have 

 reduced the temperature of pasteurised cream as much as 100 degrees with 

 water circulation alone. Another method is to have jacketed tanks. Still 

 another method is to have agitators in the cream vats. One other point is 

 that cream which has been pasteurised makes a butter of better texture. 



