Unfilterable Beer Haze Part I: The Investigation of an India Pale Ale Haze

Abstract

The nature of undesirable and unfilterable haze particles observed by craft breweries remains nebulous and presents a challenge when the aim is the production of bright beer. A commercial beer was studied in which the brewery had sporadically encountered unfilterable haze. In this study, it was hypothesized that unfilterable haze particles were formed due to increased concentrations of proteins, polyphenols, and/or beta-glucans. Samples of a high haze and low haze India Pale Ale were degassed and digested with enzymes amyloglucosidase, pepsin, and UltraFlo Max (Novozymes TM ). Additionally, the protein, polyphenol, and beta-glucan content of each sample was measured. When comparing protein, polyphenol, and beta-glucan concentrations substantial differences between high haze and low haze protein concentrations were observed. Due to the unfilterable nature of these hazes, combined with experimental findings, it was hypothesized that yeast cell-wall proteins were responsible for this haze. Understanding of the source of these hazes offers brewers the opportunity to mitigate against their formation by adjusting brewing practices. Experimental SamplesThe control sample was a lager that had not been dry hopped, which had consistent low levels of turbidity < 1.0 EBC (European Brewing Convention) units and was produced in the same brewery as the experimental beers. The experimental beers used in the study were industrially

Effects of Dry-Hopping on Beer Chemistry and Sensory Properties—A Review

“…Huismann et al [ 139 , 140 ] found in unfilterable dry-hopped India Pale Ale, that the haze was caused by β-glucans and proteins. The authors suggested that this type of haze was due to the presence of unfilterable yeast cell wall mannoproteins in the beer.…”

“…In a study by Ferreira et al [ 97 ], the severity of chill haze in dry-hopped beers stored for 24 months highly correlated with the content of flavan-3-ol monomers and oligomers in fresh beer and the degradation of these compounds during storage. A decrease of 1 mg/L in the content of these compounds resulted in an increase in the chill haze of 1.7 EBC unit (where EBC is a color unit of the European Brewery Convention, EBC unit = A430 × 25 × dilution factor) [ 97 , 139 , 140 ].…”

A Rapid Method for Testing Filtration Performance of Malt and the Optimization of the Method

“…Therefore, the efficiency of proteolytic hydrolysis was higher than that of amylase and glucanase. In case the proteins are not decomposed, they can give rise to turbid particles resulting in turbid wort [30]. Thus, the filtration efficiency of malt can be evaluated and predicted based on this observation.…”

Proteomics and glycoproteomics of beer and wine

“…The causes of this unfilterable haze are not completely clear, but it is associated with high concentrations of proteins, polyphenols and β‐glucans. A proteomics based study of commercial India Pale Ale diagnosed that overall protein and β‐glucan content were associated with this haze, and postulated that cell wall mannoproteins secreted by yeast were the primary cause [56]. A follow‐up study used protein fractionation, SDS‐PAGE and LC‐MS to reveal that both yeast cell wall mannoproteins and flocculins Flo1 and Flo9 were the most abundant proteins associated with unfilterable haze, providing avenues for future research to avoid problematic haze formation [57].…”