Babcock test

The Babcock test is the first inexpensive and practical test factories could use to determine the fat content of milk.

Until the 1890s, dishonest farmers could water down their milk or remove some cream before selling it to the factories because milk was paid for by volume. Honest farmers, as well as those that produced naturally rich milk, were not being compensated fairly.

Stephen Moulton Babcock researched the problem at the University of Wisconsin–Madison and developed the following process:

Key to this process is that everything in milk except the fat dissolves in sulfuric acid. The fat floats to the top. The centrifuge ensures complete separation with no bubbles in the fat, and the fat content can be measured using the graduations on the test tube and knowing the initial amount of milk used.

After the development of the test, it was much easier for a dairy operation to not only compensate farmers fairly, but to produce a consistent product that consumers could depend on. The Babcock test was also utilized by farmers to selectively breed for cows who produced milk with higher butterfat content—the tests were usually done monthly by an employee of the local Dairy Herd Improvement Association (DHIA).

In 1911, the American Dairy Science Association's Committee on Official Methods of Testing Milk and Cream for Butterfat, chaired by O. F. Hunziker, met in Washington DC with the U.S. Bureau of Dairying, the U.S. Bureau of Standards and manufacturers of glassware. Standard specifications for Babcock glassware were published as a result of this meeting.

Professor Babcock patented his invention, bringing global recognition and praise from farmers that could now cheaply test the quality of their milk.

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Wikipedia