a method of cooling blown film consisting of thermoplastic plastics during the production of blown film by means of a blown film extruder with a film blowing head which comprises an annular nozzle from which the blown film emerges and is guided away in an extraction direction , wherein at least two cooling gas flows are made to approach the blown film from the outside in at least two blowing - out planes located at a distance from the annular nozzle , wherein at least one cooling gas flow k g is blown out in the direction opposed to the extraction direction of the blown film and wherein at least one cooling gas flow k a is blown out in the extraction direction of the blown film , and wherein , at least one of the cooling gas flows k g , k a can be controlled around their circumference in sectors , at least in respect of its volume flow or temperature .