For the first time, previously unknown multiple reaction stages have been identified during the reduction of silver ions in the high-temperature polyol process of synthesizing silver nanowires. New in situ potentiometric silver ion measurements clearly show different phases of the crystal growth process along the reaction path as silver ions are reduced to metallic silver. Incorporation of nitric oxide monitoring of the reaction headspace gases provides additional insight into the reactions affecting the silver ion reduction process. The combination of monitoring the Ag+ ion concentration with evolved nitric oxide demonstrates that the reduction of silver ions to form crystalline silver of various morphologies in the polyol process is far more complicated than previously realized. These new approaches also provide powerful new tools to study other elevated temperature metal reduction reactions.