Prior to the modern era, in the process of mixing koji and water, yeasts naturally existing in the air were taken into or "yeast of the house" or "yeast of a brewing house" were utilized.
近代以前は、麹と水を合わせる過程において空気中に自然に存在する酵母を取り込んだり、酒蔵に棲みついた「家つき酵母」もしくは「蔵つき酵母」に頼っていた。