Dekoji buai (finished koji water absorption rate)

Dekoji buai is an indicator of the water absorption rate of dekoji (finished koji), expressed as the ratio between the amount of rice used for the dekoji and the amount of polished rice. It is calculated with the following formula: dekoji buai (%) = ((weight of dekoji (kg) − weight of polished rice (kg)) ÷ weight of polished rice (kg)) × 100. This figure is important for understanding how the rice absorbs moisture and how that affects fermentation, and it is one of the factors that influence the quality and flavor of sake. A high dekoji buai indicates that the koji absorbs moisture readily, and in sake brewing this calls for production methods that make use of that characteristic.