In the past, sake foam rose above the brim of a barrel due to fermentation and the sake sometimes ran over the barrel in the course of main fermenting mash preparation, and once this occurred, it could lead to a large amount of waste of the prepared sake, so breweries needed staff whose task was to keep watching their sake all night long.
昔は日本酒醪の最中に、醗酵のため泡が盛り上がってきて、ときには酒が樽から溢れ出ることがあり、それが起こると多量の仕込み酒が無駄になったので、徹夜でそれを見張る係が必要だった。