Milk that you purchase in the store has been homogenized so you can't skim off the cream. During this mechanical process, the milk fat globules are broken down so they integrate into the milk and do not float to the top. Machines are responsible for separating the cream you buy in the store. But if you have access to nonhomogenized or raw milk straight from the cow, skimming the cream is relatively simple. It just requires a little patience and a delicate hand.
Production plants separate cream from the milk through a process known as centrifugation. The milk is placed into large vats and then rotated a high speed until the milk fat, or cream, separates and the desired fat content is attained. Whipping cream contains at least 35 percent milk, for example. The cream is then pasteurized to kill any potential pathogens.
A few national milk producers sell nonhomogenized milk in regular supermarkets. You may find it labeled "cream on top" as well as "nonhomogenized." In some states, you're permitted to purchase raw milk, which is nonhomogenized and unpasteurized. Both types of nonhomogenized milk will have a decent amount of cream visible at the top. During transport, some of this cream may integrate back into the milk, so you'll need to let it sit for several hours, or preferably overnight, to allow most of the milk fat to rise back to the top. Longer rest time results in a thicker cream.
Skimming the Cream
Use a ladle or large spoon to gently skim the cream off the surface of the milk. Spoon it into a clean jar for storage. If you're not so adept and get too much milk into your cream, simply let it sit again for several hours and re-skim. If there's only a small bit of milk settled at the bottom of your milk jar, James Ranch suggests using a turkey baster to suck it away.
Raw Milk Caution
Raw milk is illegal in 18 states because it increases your risk of exposure to food-borne pathogens. Children, the elderly and people with compromised immune systems are usually most vulnerable to infection.