This page is from the Clausius-Clapeyron Program on-line help.
The aw of a material at
a given moisture is dependent on temperature. As temperature increases,
isotherms shift down and to the right as shown below. Thus, at
constant moisture content, the water activity increases with temperature.
This may influence shelf stability.
This effect has been modelled by the Clausius-Clapeyron equation.
If you measure the Aw of a material at at least two temperatures over a range of moistures, an isotherm can be produced for any temperature. Aw's at three or four different temperatures will improve the accuracy.
Note: The isotherm
data at each temperature must first be entered into the isotherm
program, and stored in the database.
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