A method is provided for cooling a powder in a tunnel with a vibrating support with at least two independently controllable cryogenic liquid inflows into the tunnel. It includes the following steps. A thermal mass of powder entering the tunnel is determined. The arrival of the powder at the tunnel inlet is detected. The thermal mass measurement previously obtained is synchronized with the detection of the arrival of the powder at the tunnel inlet, according to a known or predefined response time of the means for controlling the said cryogenic liquid inflows into the tunnel. The synchronization data is transmitted to a data acquisition and processing unit, which is able to retroact, if necessary, on the basis of this data, on all or part of the parameters governing the operation of the tunnel. The method is especially applicable to the cooling or deep-freezing treatments of food products or chemicals.