14 



the boiler where the temperature will remain stationary for 20 to 30 

 minutes and cover the milk can. 



Meanwhile, have a tub rilled with cold water, preferably with ice 

 water, and place the milk can in it. Moving the can round with one 

 hand (so as to stir the water), the milk is stirred with the other hand 

 until 50 degrees cold. 



Where there is a tank with flowing cold water, it is enough to 

 stir the milk, but where neither this nor ice are at hand, the quantity 

 of water must be regulated according to its temperature. 



If, as for instance, there are 20 Ibs. of milk at 155 that 

 we desire to cool to 60 (50 would be better), we have to cool 

 20 Ibs. 95 or 1900 units. 



Supposing then we have water at our command at 48; 

 then we must theoretically have 158J Ibs. of this water to reduce the 

 milk to 60, bat practically this is not enough and it would be 

 too slow work, hence I consider that 300 Ibs. of such water would be 

 nearer the mark. 



This question of cooling is the great stumbling block which for 

 years will prevent farmers from pasteurizing the milk. Indeed, I 

 feel inclined to make the broad assertion that unless there is flowing 

 water of not more than 48 or else a good supply of ce, pas- 

 teurizing should not be attempted. 



But, as I have urged again and again, there is no reason why 

 every farmer should not lay in a stock of ice. In Sweden I had my 

 ice-heap simply covered with saw dust. There is no need of expensive 

 ice-houses, and a stock of ice will prove a blessing to the housekeeper 

 and useful for other purposes. 



As to ice, the theoretical amount required to cool 20 Ibs. 95 

 would be about 14 Ibs., but practically it will take about pound 

 for pound unless the first cooling is done with water. In that case 

 -J Ib. of ice to 1 Ib. of milk may be figured on. 



Pasteurizing costs money for fuel to heat and ice to cool, and 

 the latter is the most expensive, but even if we take the highest 

 amount of ice, the cooling will after all only cost 10 cents for 100 Ibs. 

 if the ice is $2.00 per ton. 



It is an easy matter for anyone who has a thermometer to make 

 the above experiment on a small scale and convince himself of the 

 effect. Unless more than 200 Ibs. are to be pasteurized I see no need 



