The present invention relates to a method for producing a nonalcoholic beverage by fermentation, comprising the following steps: (a) providing a providing a macerated cereal extract, (b) producing a wort from the cereal extract, (c) treating the wort from step (b) with Lactobacillus microorganisms in order to obtain a sour wort, (d) mixing the sour wort from step (c) with a liquid containing sugar and treating the mixture with Lactobacillus microorganisms in order to obtain a fermented beverage, (e) heating the fermented beverage obtained from step (d) and then cooling said fermented beverage, (f) mixing the beverage, and (g) performing further treatment steps for stabilizing, clarifying, and completing the beverage.