Abstract
Malt modification index is an important indicator of endosperm breakdown, enzyme development, protein solubilization, and starch accessibility during brewing. This study investigates the relationship between malt modification index and wort fermentability. Malt samples with different modification indices were mashed under controlled temperature, liquor-to-grist ratio, and rest conditions. Extract recovery, fermentable sugar profile, maltose concentration, maltotriose formation, free amino nitrogen, beta-glucan content, wort viscosity, apparent attenuation limit, and filtration behavior were analyzed. The results show that higher modification index improved starch accessibility and increased fermentable sugar release, leading to stronger wort fermentability. However, excessive modification reduced some body-forming dextrins and altered foam-supporting protein fractions. Lower modification samples showed slower conversion, higher viscosity, and weaker attenuation potential. The study demonstrates that wort fermentability depends on achieving a balanced modification index rather than maximizing modification alone. Proper malt selection supports predictable attenuation, stable fermentation, and beer style consistency.