Homogenisation, which breaks the milk fat globules into smaller globules that do not rise to form a cream layer during sterilization or shipping. Consequently, it diminishes creaming and may also diminish the tendency of globules to clump or coalesce. Separation of elements in a mixture of materials having different specific gravity such as cream and skim milk is achieved by special rotating machines, which are called centrifugal cream separator. Separated cream is agitated in churn in order to get butter by changing the emulsion from oil in water to water in oil.

The production of beverage milks combines the unit operations of clarification, separation (for the production of lower fat milks), pasteurization, and homogenization. The process is simple, as indicated in the flow chart. While the fat content of most raw milk is 4% or higher, the fat content in most beverage milks has been reduced to 3.4%. Lower fat alternatives, such as 2% fat, 1% fat, or skim milk (<0.1% fat) or also available in most markets. These products are either produced by partially skimming the whole milk, or by completely skimming it and then adding an appropriate amount of cream back to achieve the desired final fat content. Vitamins may be added to both full fat and reduced fat milks. Vitamins A and D (the fat soluble ones) are often supplemented in the form of a water soluble emulsion to offset that quantity lost in the fat separation process.

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