Rinse sweet rice until the water runs mostly clear
Drain the rice well
Steam or cook the sweet rice until fully tender
Spread the cooked rice in a thin layer to cool slightly
Pound or process the rice into a smooth paste
Add a little water if needed to help it become smooth
Continue mixing until the texture is fine and sticky
Dry the paste or flour mixture completely
Grind the dried mixture into a fine powder
Sift the powder to remove any coarse bits
Store the mochiko in an airtight container