REPORT OF TflE AGRICULTURIST. 91 



Cold milk has a greater density than that of milk at a higher temperature ; and 

 therefore the higher temperature up to 85 degrees, the greater the efficiency of the 

 separation, all other conditions being equal. 



Particular care should be exercised to prevent the mixing of any bitter milk with 

 the general supply. If any appreciable quantity of bitter milk be mixed, the result will 

 be a quality of butter likely to be more or less bitter in flavour. In very bad cases it 

 may become quite oily. These are both serious defects in butter. 



In creameries where the heating and cooling conveniences are rather limited, 

 to separate the milk at a temperature of 80° Fahr. will be satisfactory ; but in those 

 cases the inflow of milk should be lessened and be regulated according to the percentage 

 of fat which is discovered to be left in the skim milk. That should be reduced to one- 

 tenth of one per cent. 



The Separator. — While there are differences in the capacity and construction of 

 different separators, the efficiency of the skimming depends largely upon the skill and 

 management of the operator. The thoroughness of the separation of the fat depends, 

 mainly on : (1) The speed at which the separator is run ; (2) the temperature of the 

 milk ; and (3) the quantity of milk run through per hour. It is desirable that the sep- 

 arator be run at its maximum of speed, and that that be not exceeded. The different 

 manufacturers of separators guarantee their machines good for a certain maximum speed, 

 which is usually stamped on the bowl. 



When the quantity of cream to be separated can be regulated by a set screw in the 

 bowl, that should be set to allow from 14 to 16 per cent of the quantity of milk to flow 

 through the cream outlet. A good rule is to take off cream which contains about 25 

 per cent of butter fat. 



Ripening of the Cream. — The temperature of the cream when set to be ripened, may 

 vary from 65° to 80° Fahr. according to the season. The higher temperature is used 

 during the late fall and winter. 



The temperature at which it is set for ripening, should be maintained for about 6 

 hours, during which time it should be stirred occasionally. After that, it should be 

 left undisturbed until ripe for churning. No close cover over the cream vat need be 

 used. A clean canvas cover is sufficient. Care should be taken to purify the canvas 

 cover by boiling it frequently. 



Fermentation Starter. — It is quite important that every butter-maker should have 

 on hand a fermentation starter of a pure clean flavour and of a uniform smooth consis- 

 tency. The fermentation starter may be prepared from skim-milk which is pure, sweet 

 and free from taint. The milk should be heated to 150 degrees Fahr. and left at that 

 temperature for 10 minutes. It may then be cooled to a temperature of 80 degrees 

 Fahr., when the bacteria Culture should be added. Bacteria Cultures may now be 

 obtained in the* market from firms who deal in dairy supplies. A Culture may be 

 prepared in the manner described on page 87 of this report, or some buttermilk of pure 

 nice flavour may be used instead. In the latter case the buttermilk should be added, at 

 the rate of 10 per cent, to the skim-milk, which has been heated to 150° 

 Fahr. The can or vat in which the fermentation starter is set must be perfectly clean 

 and free from rust spots or other sources or causes of contamination. Where the butter- 

 maker has not a specially constructed fermentation-starter vat, he may use a clean tin 

 can and cover it with four ply of cheese cloth or butter cloth which has been kept 

 in boiling water for at least 10 minutes. The vessel containing the starter should then 

 be put in a place where the temperature will be maintained at from 75° to 80° Fahr. 

 until the whole is curdled. It may then be cooled down gradually. When the acid be- 

 comes quite distinct it is ready for use. Where no bad flavour exists and no difficulty 

 has been experienced in churning, it is quite safe to use the buttermilk of the previous 

 churning as a fermentation starter for the cream. If at any time the flavour of the 

 butter seems to deteriorate, a new vigorous starter should be secured and that again 

 should be renewed whenever found to be necessary. 



The fermentation starter may be added to the cream at the rate of from 5 to 10 

 per cent of the quantity of cream. 



