Concentrate freezing differs quite radically from freezing water into ice. Actually, the freezing of citrus contentrate is more a process of congealing than freezing, since there is no clear heat of fusion as there is in freezing ice. When freezing water, the temperature drops almost consistantly 1° per pound for each BTU of heat removed. When the temperature reaches 32°F., no further decline of temperature takes place until 144 BTU have been removed from each pound of water and we have a change of state, or a change from liquid to solid. After water freezes to ice, additional heat can be removed as specific heat, but there is no additional heat of fusion.
Paper published with permission.