Experimental determination of the amount of ice instantaneously formed in high-pressure shift freezing

The main aim of this paper was to experimentally determine the amount of ice instantaneously formed after expansion during high-pressure shift freezing (HPSF). To do that, an easy, quick and cheap procedure was developed able to obtain accurate ice ratio estimations from temperature data of the sample after the pressure release. Very different pressure and temperature conditions, both near and far from the melting curve liquid–ice I, were chosen to produce different amounts of ice after expansion in HPSF experiments. Sucrose solutions of several concentrations (10%, 20%, 30% and 40% w/w) were also employed to study the influence of the water content of the sample. Good agreement was found between experimental estimations and theoretical predictions from the heat balance model for all the pressure and temperature conditions tested. The results showed that increasing pressure at a given temperature before expansion is an effective and fast way to increase the amount of ice produced.