The use of palm sap sugar as chocolate sweetener results in chocolate with relatively high viscosity due to the presence of high moisture and/or amorphous sugar. To overcome this problem, approaches to maintain the chocolate viscosity that can be easily and feasibly applied by small-scale chocolate producers are highly required. In this work, chocolate was produced using combination of ball mill and a mixer equipped with vacuum pump. Modification of processing method using a longer duration of the vacuum process and modification of formulation by increasing lecithin concentration were challenged. To evaluate the effect of vacuum process, palm sap sugar-sweetened chocolates were produced without vacuum process, with 10 min of vacuum process and with 60 min of vacuum process during dry mixing. As reference, sucrose-sweetened chocolate was produced using 10 min of vacuum process. Ten minutes of vacuum process was the vacuum duration used during dry mixing in the previous studies. The results showed that the use of 60 min of vacuum process was most effective in evaporating moisture which resulted in a lower viscosity. Hence, 60 min of vacuum process was, then, selected for the study on production of chocolates with a higher lecithin concentrations. Palm sap sugar-sweetened chocolates produced with 60 min of vacuum process were formulated with 0.6%, 0.7% and 0.8% lecithin. As reference, palm sap sugar-sweetened chocolates with 0.4% lecithin was also produced. The result showed that the higher the lecithin concentration, the higher the Casson yield value and the lower the Casson plastic viscosity were observed. Thus, the amount of lecithin added into the chocolate should consider the application of the chocolate.