Exploring Hop Varieties with Discriminating Flavan-3-ol Profiles Likely to Improve Color and Colloidal Stability of Beers

Abstract

While the Saaz aromatic variety remains classified as a total-flavanoid-rich cultivar, no inverse correlation was found between total flavanoids and the α-acid content when the dual-purpose varieties Citra, CTZ, Amarillo, Eureka!, Mandarina Bavaria, Mosaic, Polaris, and Sabro were considered. The levels of hop flavan-3-ol monomers, dimers, and trimers (quantitated by HPLC-MS/MS) appeared strongly influenced by variety and harvest year. On the other hand, the catechin/epicatechin ratio (and B3/B2 ratio) proved stable within the same variety through two successive harvest years. Among the nine herein-investigated varieties, Citra and Saaz displayed notable catechin/epicatechin ratios (>3.7 compared to <1.6 for the others), whereas Polaris exhibited the lowest monomer content (less than 800 mg/kg). These distinctive profiles could impact the colloidal and color stability of hop-forward beers.

Keywords

• dual-purpose hops
• polyphenols
• flavan-3-ols
• haze
• color
• epicatechin