Lithium-water reaction experiments were conducted at 616.5 K in a thermoelectric calorimeter in an effort to characterize the reaction in a batch-type environment. The experimental system was configured to measure both heat of reaction and hydrogen generation as small fixed-volume doses of water were repeatedly admitted to a large quantity of lithium. Heat of reaction measurements slightly declined with each successive water dose, while hydrogen generation markedly increased. These heat and hydrogen quantities, along with material and energy balances, were used to quantify gradual changes in reaction chemistry as lithium was depleted. The trends evident with heat and hydrogen generation indicated the formation of lithium hydride and lithium oxide as intermediates. These products, in competition with unreacted lithium, reacted with additional water to yield hydrogen and lithium hydroxide. In conclusion, these experiments provided a quantitative understanding of how reaction chemistry changes when water is continuously added to a lithium bath.