Milk Fat

Milk is made up of 87.3 percent water, 3.9 percent milk fat, and 8.8 percent nonfat solids such as proteins, lactose, minerals, acids, enzymes, gases, and vitamins.

Milk is sold at various percentages of milk fat: 3.25 percent (whole or homogenized), 2 percent, 1 percent, and skim (nonfat). Before mechanization, fresh milk was left to separate naturally, taking 12 to 24 hours. The cream was then “skimmed” from the surface and the remaining milk was referred to as the skim. Today, dairies use centrifugal cream separators to save time. The cream is then packaged or used to make butter or it is added back to the skimmed milk to achieve the desired milk fat percentages. Milk with 3.25 percent milk fat is often referred to as whole milk because practically almost all of the natural milk fat is present. It is also called homogenized, referring to the process to keep the milk from separating.