Section III, 1917 [loi] Trans. R.S.C. 



The Determination of the Moisture-content of Flour. 

 By Frank T. Shutt, D.Sc, and P. J. Molonev, M.A. 



(Read May Meeting, 1917.) 



Shortly after the outbreak of the war it became necessary to 

 undertake in the laboratories of the Dominion Experimental Farms 

 system the weekly determination of the moisture content of a con- 

 siderable number of flour samples. As it was found that the pro- 

 cesses employed for this purpose in commercial and milling labor- 

 atories differed widely in what appeared to be essential particulars, 

 an analytical review of the several drying methods in vogue was 

 made. This work showed that very considerable discrepancies 

 between the several processes existed and that the moisture content 

 obtained might differ by as much as 2 per cent, according to the 

 methods employed. For our purpose it was of paramount import- 

 ance to adopt a method that would be at once reliable and accurate, 

 giving results as close to the absolute truth as the inevitable experi- 

 mental error would permit and which at the same time did not entail 

 any protracted operations or the use of complicated apparatus. 

 This paper presents in a very concise form the more important results 

 of an investigation to find such a method, together with our con- 

 clusions therefrom. 



The methods herein considered comprised those employing 

 (a) the Freas electrically heated vacuum oven in_ which a steady 

 vacuum of 29-5 inches was maintained, (b) the Freas electrically 

 heated air oven and (c) a double jacketed water oven or steam bath 

 drying at ordinary atmospheric pressures and heated by gas. The 

 temperature of this latter oven would be approximately 2°C. below 

 the boiling point of water. 



It was not found practicable to use the same sample throughout 

 the whole investigation, but this did not interfere with the accuracy 

 of the deductions made, since the results in each set of comparisons 

 were obtained on the same flour. 



The drying of the flour was made in aluminium dishes, 4-5 

 cm. in diameter by 2 cm. in depth, furnished with tightly fitting lids 

 which were immediately replaced on the removal of the dishes from 

 the oven and before they were put in the desiccator to cool. Approxi- 

 mately 2 grams of flour, weighed to (,\ milligram, were taken through- 

 out the work. 



