Early Separators Helped the Cream Rise to the Top

Let's Talk Rusty Iron: Early separators were a boon to farm and dairy.

| May 2008

For thousands of years cream was separated by the slow and inefficient method of pouring raw milk into various containers and letting gravity move the less dense cream to the surface where it could be skimmed off.

In 1859, an obscure German brewmaster discovered he could easily separate cream by swiftly rotating a barrel of milk. But since the German was in the beer business instead of dairying, he didn't pursue the idea.

During the 1860s, a Danish horse doctor named Jensen rigged up a vertical pole with a crosspiece at the top. He hung a pail of milk from each end of the crosspiece and contrived to whirl the whole contraption. After spinning the device for about a half hour, the Dane found thick cream on top of the milk in the pails.

In the 1870s, several European inventors worked on the problem of large-scale separation of cream from milk. A German engineer named Lefeldt perfected a machine consisting of a large tub filled with milk and spun by a steam engine at 800 rpm. Lefeldt's machine took 15 to 20 minutes to fully separate the cream and was available in four sizes capable of handling 110, 220, 440 or 660 pounds of milk per hour. Another prominent maker of separators during that time was Neilson & Peterson, whose Danish-Weston machines were widely imported into the United States.

These large capacity machines were used primarily in large creameries and were expensive and slow. The small hand-powered continuous cream separator found on most dairy farms during the first half of the 20th century had yet to be thought of.

The small separator became possible in 1879, when Swedish engineer Gustaf de Laval perfected the "continuous centrifugal cream separator." Before that, all cream separators had a tank that was filled with milk and spun to separate the cream. The cream was then skimmed off and the tank emptied of skim milk. After washing and refilling the tank with raw milk, the procedure was repeated.