As for Fermenting yeast, mainly the natural yeast in the air or the yeast living in the brewery since old times (referred to as yeast in storehouse or yeast in house) were used.
醗酵を進める酵母については、酒蔵では空気中に自然に存在する酵母や、昔から住みついている酵母（蔵つき酵母・家つき酵母）の力に頼っていた。