Some decades ago, the oxidation of sulfurous acid in aqueous solution was described as a probe reaction to characterize carbon-based catalysts in redox reactions. Since then, the importance of porous carbon materials in the redox catalysis increased enormously because of the new challenges in developing energy-saving alternatives to industrial catalyst systems or catalysts for energy conversion applications. Therefore, there is an growing interest in rapid and reliable tools to characterize such catalysts. However, the use of oxidation of sulfurous acid as a test reaction fell appearently into oblivion. The aim of the present article is to evaluate its potential and limitations and to suggest improvements.