The present invention provides a method for improving bitterness stimulation of an effervescent beverage containing iso-α-acid, or the like, the method including adjusting an NIBEM value of an effervescent beverage containing iso-α-acid to 75 seconds or less, wherein a bitterness value of the effervescent beverage is 8 to 25 BU.本發明提供一種包含異α酸之發泡性飲料之苦味刺激之提升方法等,其包括:將包含異α酸之發泡性飲料之NIBEM值調整為75秒以下,且上述發泡性飲料之苦味價為8~25 BU。