A transitiometric in situ analysis of wheat starch aqueous suspensions heated over a temperature range from 285 K to 415 K under isobaric conditions of 10 MPa is presented. Measurements were performed at four selected water concentrations: 56.0%, 64.7%, 73.5%, and 82.4% weight/water. Thermal and volumetric properties and their water content dependencies have been determined for three successive starch phase transformations occurred during wheat starch gelatinization.