Abstract: In a method of manufacturing a dispensing system for dispensing a product from a canister, comprising a solid/gas arrangement in which the gas is adsorbed onto the solid under pressure and desorbed therefrom when the pressure is released and in which the solid comprises activated carbon and the gas comprises at least one of nitrogen, oxygen or mixtures thereof including air, carbon dioxide, nitrous oxide and argon, the canister having valve means to allow the gas adsorbed onto the carbon to be desorbed for generating a pressure in the canister and effect product dispense, the activated carbon is held from the time of its production up to its installation in the canister under a blanketing gas atmosphere which does not prevent the gas to be adsorbed from occupying the adsorption sites of the activated carbon in the canister.