A method including bringing a grain raw material liquid into contact with a yeast to effectively improve foam properties of a sparkling beverage, a grain raw material liquid, and a sparkling beverage are provided. The method includes bringing a first grain raw material liquid into contact with a yeast to produce a second grain raw material liquid to be used for production of a sparkling beverage. The yeast may be an inactivated yeast. The method may further include producing the sparkling beverage using the second grain raw material liquid.