Steaming Soybeans
Steaming soybeans
Japanese: 大豆の蒸煮（だいずのじょうしゃ）
Steaming soaked soybeans until soft, promoting protein denaturation for fermentation.
Soaked soybeans are heated in a steamer or pressure cooker until soft — crushable between thumb and pinky. Steaming denatures proteins for easier enzyme breakdown.
Steaming rather than boiling prevents umami from leaching into cooking water. Pressure cooker boiling is acceptable. Softness achieved determines mashability and fermentation smoothness. A pressure cooker takes about 20-30 minutes; a steamer requires 2-4 hours. Well-steamed soybeans turn golden with a warm, starchy aroma.