*"It is a very important process in fermentation during the production of beer where cells form macroscopic flocs. These flocs cause the yeast to sediment or rise to the top of a fermentation at the end of the fermentation. Subsequently, the yeast can be collected (cropped) from the top (ale fermentation) or the bottom (lager fermentation) of the fermenter in order to be reused for the next fermentation." In Sake you can expect this after storing it in a refrigeration unit and dropping the temperature to start this process after the first filtration process.
*https://en.wikipedia.org/wiki/Flocculation
