Cover the soybeans with water by 4 in/10 cm, and allow them to soak for 24 hours.
Drain the soybeans and discard the soaking liquid. Combine the soybeans with 1 gal/3.79 L cold water and purée into a very smooth slurry. If necessary, purée in batches.
Strain the purée through a fine-mesh strainer and then strain again through a cheeseclothlined strain