Method for producing sparkling fermented beverages

An object of the present invention is to provide a method for producing a sparkling fermented beverage with improved foam retention while suppressing the influence on aroma. In the method for producing an effervescent fermented beverage of the present invention, a soy protein hydrolyzate obtained by degrading soy protein, defatted soy or concentrated soy protein with a neutral protease is used as a raw material for a fermentation raw material liquid before fermentation with yeast. The phenylalanine content of the soybean protein degradation product is preferably 5% or less with respect to the total nitrogen content.