Babcock test bottles, featuring a long, thin neck with graduations from 0-50 were designed to test the fat content in cream.
The late-19th-century interest in nutrition, unadulterated foods, and truth in labeling led to a demand for a simple test to determine milk quality. At the time, milk was sold by weight. This led some farmers to water down their product or skim cream from the top, punishing honest farmers and creating an unpredictable quality in milk for the public. The University of Wisconsin tasked Professor Stephen M. Babcock (1843–1931) with finding a solution to this problem, and in 1890 he announced the Babcock test.
Earlier tests could accurately determine milkfat levels but were too lengthy and expensive to be widely implemented. Babcock’s test delivered a simple, time- and cost-effective solution that dairymen quickly adopted. The test not only provided a reliable way to determine fair prices for milk based on quality, but it also became a useful tool for animal breeding. By keeping consistent records of each cow’s milkfat production, farmers could breed their herds for improved milk.
As the test’s popularity grew, so did the demand for cheap but accurate graduated test bottles, pipettes, and graduated cylinders to carry out the test. The test required a milk sample of a standard weight, to which the tester added precise amount of sulfuric acid. The acid dissolved all of the milk constituents except for the fat, which floated to the surface. After heating and several spins in a centrifuge, the fat became trapped in the neck of the bottle. The tester could determine the percentage by reading graduations between which the fat fell.
Babcock, S.M. 1890. “A New Method for the Estimation of Fat in Milk, Especially Adapted to Creameries and Cheese Factories.” In Annual Report of the Agricultural Experiment Station of the University of Wisconsin for the Year... University of Wisconsin Agricultural Experiment Station.
Hart, E.B. “Stephen Moulton Babcock.” Journal of Nutrition 37, no. 1 (1949): 1–7.
Hunziker, Otto Frederick. “Specifications and Directions for Testing Milk and Cream for Butterfat.” Journal of Dairy Science 1, no. 1 (1917): 38–44.
Rosenfeld, Louis. Four Centuries of Clinical Chemistry. CRC Press, 1999.
Shaw, Roscoe H. Chemical Testing of Milk and Cream. U.S. Government Printing Office, 1917.
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