Abstract: A low-calorie, all-malt beer characterized by full body and flavor of a conventional all-malt beer and a method of preparing the same without any external enzymes is described. A wort is prepared by blending warm malt mash with hot water under conditions which avoid exposing the blend of hot water and the malt mash to temperature between about 52.degree. C. and 75.degree. C., and the resultant wort is converted to beer by fermenting the wort with Brewer's yeast. The wort extract is oxygenated with substantially pure oxygen in place of air normally used in the fermentation, and the Brewer's yeast is added to the wort extract at a rate of about 30 to 60 grams pressed yeast per 100 liters wort so as to absorb, within the yeast cells of the Brewer's yeast, substantially all harsh and grainy flavor compounds contained in the wort extract.