Milk Tester, "Chefaco", made by the Creamery Package Manufacturing Co., Chicago,...


Bega Pioneers Museum


Milk Tester, "Chefaco", made by the Creamery Package Manufacturing Co., Chicago, Illinois

About this object

One of the difficulties that faced the early dairy factories of New South Wales was the problem of suppliers watering down their supply to gain higher returns. Until sampling was introduced at the factory level, dairy farmers that added water to their milk to increase the quantity of their daily supply would be paid the same as their truthful associates. To prevent this practice, dairy factories implemented butter-fat testing that could be achieved by several methods. The most popular of these methods was devised by Mr. Stephen M. Babcock from the University of Wisconsin-Madison, then chemist of the Wisconsin Agricultural Experiment Station. Popularly referred to as the Babcock Method, it was first explained in the Experiment Station's Bulletin of July 1890 (No. 24).

The test worked by drawing a sample of milk and pouring it into a graduated test tube. To this sample would be added an equal part of commercially available sulphuric acid. The reasoning behind the addition of sulphuric acid was that it would destroy all solids other than the fat present in the milk. It also helped to separate the fat from the remaining contents of the sample when it was used in conjunction with the centrifugal machine.

It was important that at least some cold air entered the chamber of the centrifuge during the process, as temperatures exceeding 60 degrees Celsius (140 degrees Fahrenheit) would produce a false reading due to the expansion of fat at the high temperature. Ideally, a reading should be taken at a temperature between 43 degrees Celsius (110 degrees Fahrenheit) and 60 degrees Celsius (140 degrees Fahrenheit).

This model was worked by the rapid rotation of a crank handle positioned to the side of the chamber, however other models that utilised a steam turbine was also popular. It was important that the measurement of quantities of the sampled milk and sulphuric acid were exact. The tester would use two narrow, graduated glass measuring cylinders- one for the milk and the other for the acid. A typical test pipette (narrow lower body) or bottle (wider lower body) would have the neck graduated from 0 to 10, each division being subdivided into five parts. Each subdivision of the scale represented .2 of 1 per cent of the total content. This allowed for a very accurate reading of the butter fat content after it had been separated in the centrifuge.

A useful description of these many tests are provided by the book: Wing, Henry H., (1907), Milk and Its Products- A treatise upon the nature and qualities of dairy milk and the manufacture of butter and cheese, London: Macmillan Co. (11th ed.), pp. 35- 65.


Creamery Package Manufacturing Co.

Place Made

Chicago, Illinois

Medium and Materials

Cast iron body with small legs affixed to base. The chamber is shaped like a donut, with a large door that was attached by two hinges. The door is shaped like half of a wide orange quarter, cut horizontally through the middle. A cast iron crank handle was located to the side of the tester. It turned the inner parts of the chamber by two gears- the gear located closest to the handle is a spur gear and the other, located closest to the centre of the centrifuge is a worm gear. The gears turned the inner parts of the centrifuge around its centre axis at a rapid speed to ensure that the butter-fat would be adequately separated from other components of the sampled milk.

Inscription and Marks

721V" [Raised cast iron lettering on the outer side of the door]


AND SUPPLIES" [plate positioned at the centre of the door]

Object Type

Milk Tester

Copyright Licence  

All rights reserved

leo 19 Oct 2014 06:14 AM,UTC

i have one too. but my one is a crepaco style

Robin 19 Apr 2012 23:41 PM,UTC

The Creamery Package Mfg. Co. later became Crepaco after it was purchsed in the late 1800's and moved to Lake Mills, WI. The name change came after the turn of the century.

Rod Goodale 31 Mar 2011 00:16 AM,UTC

I have one of these milk does not say "Chefaco" on mine or the one on this says "Crepaco". I can supply a pic of mine to show you. If you look closely at the pic you can see how the mistake was made....Thank You.

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Milk Testing

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