The invention relates to a method for wetting and/or dissolving a substance contained in a capsule (3) for producing a drink. According to said method, a perforation and injection element (5) is used to pierce the capsule (3) and to inject a pressurised liquid into the same in order to trigger the wetting and/or dissolving of the substance, the perforation and injection element (5) being arranged in such a way as to inject the liquid into the capsule (3) in the form of at least one fine layer extending in a continuous, divergent and multi-directional manner, covering a spray surface according to a semi-circle inside the capsule. The invention also relates to a device comprising a flow channel (80a) and a valve (86) which is arranged in such a way as to close the channel in a first position, i.e. a neutral position, and to open under the effect of the pressure of the liquid against an elastic element (90) in such a way as to release a passage according to the pressure, and to thus create the fine layer of liquid.