Original: This can be achieved by various methods , with 1 ) solution cooling , 2 ) addition of a second solvent to reduce the solubility of the solute ( technique known as antisolvent or drown-out ) , 3 ) chemical reaction and 4 ) change in pH being the most common methods used in industrial practice .
Simplified: This can be achieved by various methods -- solvent evaporation , cooling , chemical reaction , ` drowning ' being the most common ones used in industrial practice .