Roka-ki

【English】

Filtration machine, filter

【Japanese】

ろ過機

Machines for filtering sake (as opposed to presses for filtering (pressing) moromi mash). Primary filtration uses press and leaf filters; secondary filtration uses cartridge and membrane filtration.

The filter press has plates and frames alternating together, or a series of plates alone: these are clamped together to prevent the liquid leaking out as it passes through. Leaf presses use stainless steel mesh “leaves”, which are fitted with cloth covers and assembled inside a metal frame, and the liquid to be filtered is pumped inside. This type of equipment is also sometimes called “drum” or “chamber” style. In some cases, the plates act as the filtration medium, but it is common to use cloth or paper filters pre-coated with diatomaceous earth, pulp, cellulose nanofibres or such. These kinds of apparatus are usually used for primary filtration, later followed by secondary filtration with cartridge or membrane filters. There is also equipment for ultrafiltration which can remove enzymes and other proteins from the liquid.