Explorative Study on the Interactions Between Specialty Malts and Lager Yeast Strains: Impact on Beer Aroma and Volatile Composition
Year: 2025
Type: article
Abstract: The aroma of beer results from complex interactions between raw materials and microbial metabolism during brewing and fermentation processes. While the contributions of specialty malts and yeast to the beer aroma are well documented, their interplay—particularly with lager yeast strains—remains underexplored. Thus, this study investigates how four commercial Saccharomyces pastorianus strains impact the aroma of beers brewed with 100% Pilsner, 20% caramel, or 2% roasted barley malt. Pilot scale wort production and lab scale fermentation was conducted under standardized conditions. The aroma of the beers was assessed using a trained sensory panel and applying check-all-that-apply (CATA), complemented by headspace gas chromatography-mass spectrometry (HS-GC-MS) to determine volatile composition. Results revealed that both malt type and yeast strain significantly influenced beer aroma. Roasted malt exerted the most pronounced effect, but yeast strain-specific metabolic activities also distinctly modulated aroma outcomes, especially for attributes such as coffee and caramel. Analysis of volatiles confirmed strain-dependent biotransformation and selective retention of malt-derived precursors. Multiple factor analysis showed that in some cases, yeast strain had an equal or greater impact on aroma than malt type. This study challenges the view of lager yeasts as metabolically neutral and underscores the importance of strain selection for aroma optimization in lager-style beers.
Institutions: Trier University of Applied Sciences, Lesaffre (France)
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W4417049898