Abstract
Beer haze formation is closely related to malt protein fractions, polyphenol interaction, storage temperature, and colloidal instability. This study investigates the role of malt protein fractions in beer haze formation. Malt samples with different protein profiles were mashed and fermented under controlled brewing conditions, followed by cold storage assessment. Soluble protein concentration, high-molecular-weight protein fractions, polyphenol binding tendency, turbidity, chill haze intensity, foam stability, pH, colour, and sensory quality were measured. The results show that high-molecular-weight protein fractions increased haze formation by forming complexes with polyphenols during storage. Moderate protein levels supported foam retention, while excessive soluble protein increased turbidity and reduced visual clarity. Cold storage accelerated protein–polyphenol aggregation, especially in beers with higher residual reactive proteins. The study demonstrates that haze control requires managing malt selection, mashing conditions, protein breakdown, and polyphenol balance together. Overall, malt protein quality plays a central role in beer clarity and stability.