Recent developments in understanding the nature of protein-polyphenol interactions that lead to haze are summarized and some new findings are presented. The ratio of haze-active (HA) protein to HA polyphenol has been shown to impact both haze intensity and haze particle size. Changes in particle size impact instrumental and human perceptions of haze, and also influence sedimentation and filtration behavior. Alcohol and pH also affect the nature of haze. Of these, the effect of pH is more pronounced. The greatest haze intensity and the largest haze particles occur when the pH is near the isoelectric point of the HA protein, with less haze and smaller particles at higher and lower pHs. Results of many of the analytical methods used to measure haze-active constituents are influenced by the endogenous levels of haze-active (HA) and non-HA polyphenols and of HA proteins. The non-haze active polyphenols compete with those that are haze-active for binding sites in the HA proteins; this has the effect of reducing the number of polyphenol binding sites in a HA protein molecule. The endogenous levels of HA protein and HA polyphenols contribute variable and unknown effects in a number of analytical procedures. While many of these methods are useful in a comparative sense (when the same beer is treated in different ways), calibration and quantitative measurements of HA constituents are complicated. The mechanisms of action of stabilization treatments have been studied in greater detail. Silica is specific for HA protein due to its chemical nature rather than its pore size; the most relevant property appears to be accessible surface area. PVPP binds to both HA and non-HA polyphenols. Because of this, and also because much of the HA polyphenol in beer is complexed with HA protein, the efficacy of PVPP is partially impeded.