The present invention provides alcoholic beverages which are stabilized against the growth of microorganisms whose growth may cause deterioration of the characteristics of the alcoholic beverages. The stabilized beverages are attained by utilization of a composition which includes a nisin-producing culture and a nutritional supplement in the process of making the alcoholic beverage. The composition of this invention includes nisin at a level effective for inhibiting growth of the spoilage-causing microorganisms, particularly, hardier strains of such microorganisms that may exhibit resistance to lower levels of nisin. The composition is prepared by adding to an aqueous medium, such as wort obtained in the process of making the alcoholic beverage, a nutritional supplement of a type and in an amount that is effective for increasing the yield of nisin, adjusting the pH of the wort to about 6.5, pasteurizing and cooling, inoculating the medium with a culture of nisin-producing microorganism, and fermenting the medium with a nisin-producing culture.