The stabilization of beer with proteolytic enzymes is simple and efficient. The efficiency of the enzyme treatment is not directly related to the degradation of the complex proteinaceous material, because components of colloidal haze include polyphenols, carbohydrates, and traces of metals. Proteolytic enzymes have no effect on these complexes. The stabilizing action of proteolytic enzymes is limited due to the fact that the enzyme, being protein in nature, will itself form a haze when excessive quantities are used. A considerable loss of enzyme due to adsorption, takes place during filtration of the beer; therefore, it is better to add the enzyme after filtration. The stabilization of beer with enzyme varies considerably from beer to beer and is dependent on the initial stability of the beer. The stability is enhanced if the beer has been subjected to pre-stabilization prior to adding the enzyme. Perfectly stable beers require a pre-stabilization prior to the enzyme treatment. Control of the enzyme activity alone is not enough in view of the fact that the composition of the beer is of primary importance for the stability of the enzyme treated beer. Stability tests should be carried out on storage beer and this method of testing needs to be further investigated.