THE EFFECT OF TEMPERATURE DIFFERENTIAL ON THE MOISTURE CONTENT OF STORED WHEAT

Abstract

Local increases in the moisture content of dry wheat stored in country elevator annexes have occasionally been observed in Western Canada. A laboratory experiment suggests that the chief cause is a temperature differential established during the winter. The air in the warmer parts of the grain contains a greater quantity of water vapour than that in the colder, and moisture is transferred either by diffusion or by the convective movement of the air as a whole. A temperature difference of 35 °C, across 6 ft. of grain having an initial moisture content of 14.6%, caused the moisture content at the cold end (0 °C.) to rise to over 20% in 316 days. The experiment indicates that this movement of moisture is a slow process and that equilibrium conditions are never established for any practical length of time or mass of wheat.