How are low-fat milk and skim milk made from whole milk?

Low-fat and skim milk are produced from whole milk using a process called separation, which utilizes a high-speed centrifuge known as a cream separator.

Because butterfat is lighter than the other components of milk, the separator spins the whole milk at high speeds—typically around 6,000 revolutions per minute—to create centrifugal forces that pull the denser skim milk to the outer wall of the separator bowl, while the lighter cream is forced toward the center and removed.12

Once the cream and skim milk are separated, they are remixed in precise, computer-controlled proportions to achieve the desired fat content for the final product. Generally, whole milk is standardized to 3.25 percent fat, while low-fat milk is adjusted to 1 or 2 percent fat, and skim milk (or nonfat milk) is reduced to less than 0.5 percent fat, often reaching as low as 0.01 percent.23