Milk sediment tester. (Left) c. 1950-1960. A creamery's reputation rested on how well its milk products tested for contaminants. The main source of bad-tasting milk was foreign sediments. Butter makers at the Meire Grove Creamery used this device to extract milk samples from the bottom of milk cans for testing. L. 2'3".

Babcock testing apparatus. 1950 1970. Creameries paid farmers according to the amount of butterfat in the milk they brought in. Early methods of measurement based on the natural separation of cream were crude and led to disputes between farmers and butter makers. In 1890, Stephen A. Babcock solved the problem by introducing a reliable, scientific means of measurement called the "Babcock Test," The process was fast, simple, and accurate: sulfuric acid was added to a milk sample to break down the solid fat, then placed in a special test bottle and whirled in a centrifuge. The fat gathered in the narrow graduated neck of the test bottle where it could be seen and measured. Top to bottom: Cream testing bottle. H. 6", Skim milk testing bottle. H. 5", Calipers. L. 5", Acid dipper. L. 1'4", Glass acid dipper. 8", Pipette. L. 11-1/2".

Official Babcock Test centrifuge. 1912-1924. Many dairy farmers purchased small testers to check their milk. This two-tube model was manufactured by the Creamery Package Company, Chicago. H. 7".