68 MILK AND DAIRY PRODUCTS PART 



rubber band. With the Kolibri butyrometer the rubber band 

 is not necessary, for the test-bottles are placed singly in the 

 compartments (see Fig. 30 b). 



After the test-bottles have been put into place the lid is 

 screwed on, and the disc placed in the stand, after which the 

 water-tank is put on, care being taken that the valve is closed. 

 Warm water of at least 65 C. is poured into the tank, and the 

 disc rotated with increasing speed. When the rate of speed is 

 fairly high, the valve on the water- tank is opened and warm 

 water allowed to flow into the disc. The latter soon fills, and 

 water begins to flow out of the tube of the water-tank. The 

 speed is then raised to that usual for an Alfa-Laval separator, 

 namely, 5,600 revolutions per minute, and this is continued for 

 at least five minutes. During this process warm water enters 

 by the small opening into the interior of the test-bottle and 

 drives the separated fat into the graduated part. 



At the end of the above-mentioned time ice-cold water is 

 poured into the water-tank, the disc still revolving, but with 

 diminishing speed. When the temperature of the water which 

 flows away is not higher than 12 C., the centrifuge may be 

 stopped, and the test-bottles taken out and put into the 

 wooden stand. The fat is then in a pale, homogeneous condition 

 in the graduated tube, and the column is clearly defined. 

 Each division of the scale of the test-bottle is equivalent to 

 0*2- per cent, fat, but it is quite easy to read to 0'05 per cent. 

 The number which is read off gives the percentage amount of 

 fat in the milk. 



With cream very satisfactory results can be obtained in the 

 following manner : 14 c.c. water of 30-40 C. temperature are 

 brought into a small, dry beaker by means of a pipette. The 

 cream is measured out in the usual small pipette, the outside 

 of which must afterwards be dried, and then blown into the 

 water. By repeatedly drawing up the water and allowing it 

 to flow out again, the inside of the pipette is freed from particles 

 of cream. With this mixture of cream and water the test is 

 made in the butyrometer in the ordinary way. The number 

 found on the scale is multiplied by ten, and this gives the 

 percentage amount of fat found in the cream. According to 

 investigations by the author, 1 this method gives very good 

 ] N&rdink Mejeri-Tidniny, 1899, No. 34. 



