Single-stage separation always leaves protein behind. The okara that leaves a decanter still holds between two and four percent of the original soy solids, locked in the pulp structure, and in a plant running several hundred tonnes of soybeans a year that residual fraction is worth real money. A second washing stage, where fresh water is mixed with the discharged okara and the slurry is separated again, is the standard way to recover it. The problem is that this stage needs a