Plate freezer: popular method for fish. This method keep straight shape of fish. Little amount of water may be added (glazing) to increase heat transfer and prevent freezer burn. - Air blast freezer: use with expensive products: spiral or fluidised bed system. - Immersion: use brine/sea water/ CaCl2/propylene glycol as refrigerant. T = -15 to -30 0C. - Cryogenic freezing: LN is used in particularly with shrimp