Identification of reactions that occur with the release or absorption of energy during the heat treatment of samples. The analyses can be carried out from room temperature to a maximum temperature of 1100oC, in an oven with controlled heating speed of up to 15oC/min. Endothermic and exothermic reactions are identified by temperature range and, eventually, the heat of reaction can be quantified. The technique can be used to identify the aforementioned reactions, control thermal processes and assist in identifying compounds or minerals present, as many have known reactions during heating.