Tome koji (koji for the final addition)

Tome koji (留麹) is a type of koji used when preparing the moromi (fermentation mash) for sake. The preparation of moromi is divided into three stages: the first addition (hatsuzoe, also called soe-shikomi), the second addition (nakazoe, also called naka-shikomi), and the final addition (tomezoe, also called tome-shikomi). Tome koji is the koji used in the final addition. In this stage, additional rice and water are added and fermentation proceeds, while the yeast from the previous addition is carried over. The tome koji used at this stage plays an important role in stabilizing fermentation. It influences the flavor and aroma of the batch as a whole and is one of the elements that shapes the character of the sake.