UHPLC quantification of α- and β-acids in Georgia-grown hops

Abstract

To support the emerging hop (Humulus lupulus L.) industry in the southeastern United States, a reversed-phase ultra-high performance liquid chromatography (UHPLC) method was optimized and validated to quantify α- and β-acids in 11 Georgia-grown cultivars. The method, utilizing an ICE-4 standard on a C18 column, demonstrated good selectivity, sensitivity, linearity (R² ≥ 0.999), intra- and interday precision (%RSD ≤ 3.24%) and accuracy (≥ 94.6%), indicating consistent quantification across major α and β acid constituents. Analysis was conducted on a single harvest from the 2025 growing season. Quantification of Cascade, Cashmere, Centennial, Chinook, Cluster, Columbus, Comet, Fuggle, Magnum, Nugget, and Zeus revealed significant cultivar-dependent responses under Georgia field conditions. While total α-acid concentrations in traditionally high alpha cultivars such as Zeus (118.06 mg·g–¹) and Columbus (86.08 mg·g–¹) were lower than Pacific Northwest standards, Comet (93.74 mg·g–¹) and Cascade (73.95 mg·g–¹) achieved concentrations comparable to commercial ranges. These results suggest that environmental conditions in the southeastern United States influence bitter acid accumulation; however, factors such as pathogen pressure, daily light integral, and other agronomic variables may also contribute, requiring further multi-season evaluation. Certain cultivars nonetheless show potential to produce cones of commercial bittering quality under regional conditions. Although oil composition and aroma quality remain to be analyzed for brewers, reporting the acid content is a fundamental first step in assessing the biosynthetic potential of these plants in Georgia’s environment.