Water molecules are activated to higher energy levels and break away from the water-binding sites of the food with increasing temperature. Thus, the decreasing in equilibrium moisture content is occurred. The EMC of palm sugar cake that produced from palm sugar syrup with using an open pan was higher than that produced from palm sugar syrup with using a vacuum evaporator at constant RH. This result might be explained by the different types of sugar containing in palm sugar cake product. Palm sugar cake that produced from palm sugar syrup with using an open pan contained high reducing sugar content. This due to high processing temperature and a long time during processing can promote high inversion reaction. Normally, monosaccharide such as invert sugar is hygroscopic. Hence, palm sugar cake that contained high amount of reducing sugar is rapidly absorbed water into the structure. In addition, crystallinity in the sample that produced from palm sugar syrup with using an open pan was lower than that produced from palm sugar syrup with using a vacuum evaporator. Thus, water molecules are easily penetrated into the structure, resulting in more water was absorbed.