The problem of demetallizing the wine appears in case of utilization in the wine-making industry of the equipment (tanks, pumps, presses, crushing equipment, tubes etc.) made of usual unprotected iron, that under the action of the grapes juice and, namely of the wine are subjected to the chemical corrosion, the wine is enriched with the iron ions which give to it a metallic taste. In order to restore the initial taste of the wine it is necessary to remove thereof the iron ions by administration of the potassium hexacyanoferrate(II) binding the ions of iron in the form of the thin precipitation – the Prussian blue.