Tofu and tempeh, derived from soybeans, are widely consumed for their nutritional value and high protein content. However, the production of these foods generates nutrient-rich wastewater that poses environmental challenges while offering opportunities for valorization. This study investigates the production of volatile fatty acids (VFAs) and acetic acid from tofu and tempeh wastewater via batch anaerobic digestion, utilizing various pretreatment methods. The pretreatments included adjustment of the pH to 6 and inoculum treatments with and without heat shock under mesophilic and thermophilic conditions. Results demonstrated that the highest average total VFA concentrations of 10.08 and 9.79 g L−1 were achieved for tempeh at T3 (tempeh wastewater + pH 6 + thermophilic + heat shock) and tofu wastewater at TF3 (tofu wastewater + pH 6 + thermophilic + heat shock), respectively. The highest acetic acid concentrations were observed under mesophilic conditions, reaching 77.32% for tempeh wastewater at T7 (tempeh wastewater + unadjusted pH + mesophilic + heat shock) and 92.40% for tofu wastewater at TF10 (tempeh wastewater + pH 6 + mesophilic + non-heat shock). Notably, increased VFA production was associated with reduced cumulative methane yields, such as 3.65 mL g−1 volatle solid (VS) for tempeh at T3 and 25.23 mL g−1-VS for tofu wastewater at TF3. These findings indicate the effectiveness of the pretreatment strategies in enhancing VFA and acetic acid production, suggesting significant potential for industrial applications. Further research is recommended to optimize production processes and explore the broader utilization of VFAs and acetic acid in the bioeconomy, promoting sustainability.