COD (Chemical Oxygen Demand)

COD (Chemical Oxygen Demand) is an indicator of the degree of pollution in water caused by organic matter. Specifically, a specific reagent is used to oxidize the organic matter in a water sample, and the amount of oxygen consumed in the process is measured, which expresses the degree of pollution as a numerical value. In sake brewing as well, the quality of the water used in production is considered important, so the COD value serves as one means of evaluating the cleanliness of brewing water. A high COD value indicates a greater presence of organic matter, which may affect the quality of the sake. Using good-quality water is therefore an essential element in brewing delicious sake.