Butter is defined is a fat concentrate product obtained by churning. Cream, gathering fat into a compact mass and working it. Butter is made exclusively from milk or cream with or without common salt and colouring matter and contains not less than 80% fat. In butter, fat is present in continuous phase and water is present in dispersed phase. This phenomenon is known as phase inversion.
As milk enters the bowl at the top, it is distributed to the disks through a series of openings, having speed of approx. 6,000 to 8,000 rpm, the heavier skim milk is thrown to the outer edge of the bowl and led off through an opening.
The cream concentrates in the centre portion and moves to the cream outlet.
The most efficient separators leave less than 0.01 percent fat in the skim milk.