BrewingScience issue May/June 2026 out now

In June 2026, the latest BrewingScience issue was published online. The scientific online-journal BrewingScience features peer-reviewed scientific papers with impact on the brewing industry. The brief article abstracts below provide a good initial overview of the content.

UHPLC quantification of α- and β-acids in Georgia-grown hops (Z. Hutzell, S. O. Ogundipe, D. Zhang, J. H. Suh)

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.

Solid-state fermentation for enhanced brewers' spent grain protein valorisation: A comprehensive review of conventional and emerging techniques (J. Zhang, A. E. Herrero, A. Perez-Gavilan, A. Cunha Neves)

Growing demand for sustainable plant-based protein sources has increased in recent years. Brewers’ spent grain (BSG), the most abundant brewing by-product by volume, has attracted considerable attention due to its high protein content (18 to 30%) and its desirable physicochemical and nutritional properties.

In this review, the advantages and limitations of conventional and novel BSG protein (BSGP) extraction techniques were discussed and compared. Solid-state fermentation (SSF) was highlighted as a sustainable and industrially adaptable biological process that enhances protein accessibility and recovery for waste valorisation.

The commercial viability of SSF-regulated BSG bioconversion, key operational factors and future insights were also examined. Overall, this review provides an updated evaluation of BSG protein extraction methods, thereby contributing to the advancement of sustainable resource utilization and promoting circular bioeconomy.

Influence of high concentrations of aldehydes added at mashing-in on beer flavor stability: no evidence for direct contribution to aged beer aldehydes (M. Ditrych, W. De Sutter, G. De Rouck, G. Aerts, M. L. Andersen)

Aldehydes are key markers of beer flavour stability, however, their origin during brewing and ageing remains debated, particularly with respect to de novo formation and release from bound-state forms. The present study investigated whether aldehydes present at the mashing stage contribute to the pool of free aldehydes in beer after fermentation and ageing. A mixture of selected aldehydes (2-methylpropanal, 2-methylbutanal, 3-methylbutanal, methional, phenylacetaldehyde, furfural, hexanal, and trans-2-nonenal) was added at mashing-in at concentrations corresponding to 3-fold and 10-fold levels relative to those quantified in a reference mash.

Beers were produced in pilot scale and aldehyde concentrations were analysed in fresh samples and after 90 days of forced ageing at 30 °C using HS-SPME-GC-MS. The addition of aldehydes at mashing-in did not result in increased concentrations of free aldehydes in fresh beer. After forced ageing, all variants exhibited comparable aldehyde levels, and no consistent dose–response relationship between initial and final aldehyde concentrations was observed.

These findings indicate that aldehydes present at early stages of brewing do not persist as a direct source of free aldehydes in finished or aged beer. The results indicate that aldehyde levels in aged beer are primarily determined by reactions occurring during storage, particularly Strecker degradation and other thermally driven pathways, rather than by the initial concentration of free aldehydes in the mash.