Centrifugal machine

The Babcock test developed by Dr. S.M. Babcock, Chief Chemist of the Wisconsin Experimental Station was first presented to the dairy industry in 1890. This test was one of many which had been devised in North America and Europe at about the same time to test the butterfat content in milk. Of these the Gerber Test is noteable because of its similarity to the Babcock Test. The Gerber Test was commonly used in Europe but was not popular in North America.

To be successful, a test had to be not only accurate but practical enough to be used in dairy factories and on farms. The Babcock Test involves taking a measured sample of milk and mixing with it an approximately equal volume of sulphuric acid in a test bottle with a narrow graduated neck. The acid destroys the solids not fat in the milk. The bottle is centrifuged to separate the fat from the other contents in the bottle. Hot water is added to raise the level of the fat up into the graduated neck of the bottle, the length of fat column in the neck of the bottle is measured to determine the butterfat content of the sample. With slightly different techniques and apparatus, fat content of cheese, cream or skim milk can be determined.

Milk testing by "Gerber" method

The Babcock test, since its adoption, has been a most useful indicator of milk quality for trading purposes. With the use of the Babcock test dairymen were able to accurately measure the quality of milk production from individual cows. This information is invaluable in planning breeding programs. Babcock could have patented the test and profited by it but he very generously gave it to the dairy industry.

Apparatus for measuring fat column accurately

Transferring sample of milk from pipette to test-bottle

Testing Milk and Its Products Today

Today electronic equipment that can determine the fat content of milk in as little as 30 seconds is used by dairy plants and herd testing associations.