Kumimizu buai (water-to-rice ratio)

Kumimizu buai (汲水歩合) is an indicator of the proportion of rice weight relative to the amount of water used in brewing. It is expressed as a percentage (%) and is normally calculated using the amount of water drawn in relation to the total weight of rice up to the final addition (tomezoe, 留添). A standard range is generally considered to be 125% to 130%. Specifically, it is calculated with the following formula: kumimizu buai = (liters of brewing water up to the final addition / kg of total rice up to the final addition) × 100. For the shubo (yeast starter), the kumimizu buai indicates how much water is used relative to the total weight of rice used in the starter. Because kumimizu buai has a major influence on the flavor of the sake and on fermentation efficiency, it is an important factor.