A method for determining a fraction of an adsorbed material contained in a formed body serving as an adsorber material. For the case in which the adsorber material is present in the form of a formed body, at least two electrodes are arranged, spaced apart from one another, on a surface of the formed body and/or are firmly inserted in the formed body; that, for the case, in which the adsorber material is present in the form of a powder or granulate, a corresponding formed body made of the same material is durably inserted in the powder or granular material. The electrodes are supplied with an alternating electrical current, whereby an electrical characteristic variable is ascertained; and, based on the characteristic variable, degree of saturation of the adsorber material is ascertained. Furthermore, a corresponding apparatus is claimed.