An infusion keg for a beverage is formed as a cylinder closed at both ends. An interior of the cylinder is purgeable with a purging gas to expel air therefrom and being fillable with the beverage. The keg is also provided with a valve to control entering of the purging gas and the exiting of the beverage; and an infusion port for the insertion of a permeable body having a flavorant therewithin. Upon being purged, a permeable body being inserted, the keg is filled with the beverage that, over a given period of time, absorbs a reproducible volume of the flavorant.