Oshibune (pressing in the fune, traditional press)

Oshibune (押槽) refers to the key step in sake brewing in which the moromi (fermentation mash) is pressed to separate it into sake and sake lees (sake kasu). Traditionally, the moromi was packed into sake bags (sakabukuro) and the bags were arranged in a fune (traditional press) and pressed. Automated moromi presses are now common, but the traditional method still persists. The process begins with filling the sake bags with moromi and stacking them in the fune. The first sake to come out at this stage is called Arabashiri. After the bags have been stacked, a frame (kasawaku) is placed on top and more bags are piled above it to apply pressure. For roughly the first three hours, the sake flows out slowly and naturally under the weight of the bags themselves; this stage is called mizubune (水槽). Once the height of the stacked bags has dropped, the kasawaku is removed and full-scale pressing begins, using a pressing lid (oshibuta) and timber supports (makuragi). This whole series of operations is oshibune. When oshibune is finished, the bags are restacked and pressed once more. This step is called semebune, and the sake that comes out at this point is called seme. The sake that comes out after the Arabashiri is called nakadare, and it is an important element in determining the flavor and quality of the sake. Oshibune is an extremely delicate and important process in sake brewing, and it has a major influence on the taste and aroma of the sake.