 ETN will precipitate as big platelets with bulk density of about 0.3 g/cm3 (fluffy material) when the ETN/ethanol solution is quickly poured into several liters of cold water.Smaller, fine crystals are produced by slow addition of water in said ETN/ethanol solution with intense mixing.Very fine crystals can be prepared by shock cooling of warm ETN/ethanol solution in a below -20°C cooling bath.