CHURNING OF MILK. 173 



point of view, that sweet-cream churning should become general. 

 Even although sweet cream is not so easy to churn, and yields 

 always, even under the most favourable circumstances, less butter 

 than sour cream of a similar percentage of fat, yet this is amply 

 compensated for by the great advantage which is offered by being 

 able to dispense with cream-souring. The fact that, notwithstanding 

 this, sweet-cream churning is at present only practised to quite a 

 slight extent, is chiefly to be accounted for by the fact that by far 

 the larger majority of consumers prefer the light aromatic flavour 

 of butter made from sour cream, and that only a few know how to 

 appreciate the fine flavour of sweet-cream butter. In the year 

 1874 the director of the manufactory for making preserved butter 

 in Copenhagen, Herr Busck, junr., put himself to a great deal of 

 trouble to introduce the churning of sweet cream into the dairy 

 districts of Denmark and South Sweden. For several years this 

 movement seemed to make good progress, but even as early as 

 the year 1882 this method of butter manufacturing was being 

 given up, and at present, so far as the author is aware, in all 

 dairies where sweet-cream butter was formerly made, sour cream 

 is now again churned. The careful experiments carried out in 

 Denmark at that time showed that the yield of butter from sweet 

 cream, when the improved Holstein butter churn was used, was only 

 2 or 3 per cent less than that from sour cream containing a similar 

 percentage of fat, provided the sweet cream was churned at an 

 initial temperature of 11*25 to 12*50 C., and the churn was worked 

 at the rate of about 150 revolutions per minute, churning being 

 carried out in 25 or at the most 30 minutes. The butter-milk left 

 behind from sweet-cream churning assumes very commonly, in a very 

 short time, a bitter acrid taste, which becomes especially distinct if 

 the butter-milk be slowly warmed. This is probably to be traced to 

 the action of certain kinds of bacteria, which can develop in liquids 

 showing an amphoteric or neutral reaction, but not in those possess- 

 ing an acid reaction. Even in sweet-cream butter, which has been 

 kept for some time, a bitter flavour is often found in addition to the 

 rancid flavour. 



94. Churning of Milk. As has already been pointed out in 90, 

 it is not economical to churn absolutely sweet milk, since it has 

 not yet been found possible to obtain from it even approximately 

 the same quantity of butter as is obtained in the churning of 

 sour milk. As a rule, milk 24 and 36 hours old is churned, viz. 



