Abstract: This invention provides a method for rapidly measuring an premature yeast flocculating factor of malt contained in a brewing material, comprising the following steps of: (1) mixing yeast in the late logarithmic growth phase or thereafter with a water-extracted high molecular fraction prepared from a test material sample in a buffer solution and suspending the mixture in the buffer solution; and (2) irradiating the suspension obtained in the step (1) with visible light, photographing the scattered light with a camera device, image-analyzing the image data thus obtained and determining the degree of whiteness of the suspension to measure the degree of sedimentation of the yeast in the suspension. According to the present invention, the premature yeast flocculating factor of malt contained in the brewing material can be measured in a highly accurate, rapid and simple manner, and, further, even a plurality of analytes can be rapidly measured.