Normality (kitei nodo)

Term: Normality (kitei nodo, 規定濃度) Normality is a standard for expressing the concentration of a particular chemical substance, usually the amount of solute contained in one liter of solution. In sake, it is especially important as the concentration of the sodium hydroxide (NaOH) solution used when measuring acidity. In general, 1N (one normal) refers to a solution containing one gram equivalent of NaOH per liter, but the acidity of sake is measured with a one-tenth normal (0.1N) NaOH solution. In this case, 0.1N sodium hydroxide contains 0.1 gram equivalent of NaOH per liter, which is about 4 grams. This standard makes it possible to measure the acidity of sake accurately and to control its quality.