Albumin refers generally to any protein with water solubility, which is moderately soluble in concentrated salt solutions, and experiences heat coagulation (protein denaturation). Substances containing albumin, such as egg white, are called albuminoids.
For wines, tannin stability is normally achieved by adding fining agents such as egg albumin, gelatin, or casein. The positive charge of the proteins attracts negatively charged tannins. The formation of protein-tannin complexes is a function of the balance between the number of sites that the tannin and the protein can form. Once formed, the complexes may be removed quickly by filtration or centrifugation if early bottling is desired. The removal of excess tannins reduces a major source of astringency, generates a smoother mouth-feel, reduces the likelihood of oxidated casse, and limits the formation of sediment following bottling.