Aroma and Metabolite Analysis Using GC-MS and LC-MS and Approach to Craft Beer Development

Significance of the Topic

A precise and comprehensive analysis of aroma and metabolite profiles in craft beer is essential for quality control, product differentiation and innovation in brewing. Integrating gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–mass spectrometry (LC-MS) techniques provides objective, reproducible data that complement traditional sensory evaluation, enabling brewers to fine-tune flavor development and ensure consistent product quality.

Objectives and Study Overview

This study aimed to develop a multi-omics analytical workflow to characterize aroma and metabolite differences in beers fermented with two commercial yeast strains (London Ale and American Ale) and two naturally derived wild yeasts. Key objectives were:

• Comprehensive aroma profiling using GC-MS and the Smart Aroma Database™
• Targeted metabolomics by GC-MS (derivatization) and triple-quad LC-MS
• Non-targeted metabolomics using quadrupole time-of-flight LC-MS (LC-QTOF)
• Multivariate data analysis (PCA, volcano plots) to identify yeast-driven flavor markers
• Practical application of analytical insights to develop a new craft beer

Methodology and Instrumentation

Beer samples (5 g plus NaCl) from four yeast fermentations were analyzed as follows:

• Aroma analysis: HS-20 NX headspace sampler coupled to GCMS-QP2020 NX single-quad GC-MS; Smart Aroma Database™ Ver. 2 for scan, SIM and MRM screening, followed by PCA
• Targeted metabolomics:
  • GC-MS (GCMS-TQ8040 NX, Smart Metabolites DB Ver. 2) with MeOx-TMS derivatization and AOC20i+s auto-injector
  • Triple-quad LC-MS (LCMS-8060 NX on Nexera X3) using Method Package for Primary Metabolites Ver. 3
• Non-targeted metabolomics: Quadrupole time-of-flight LC-MS (LCMS-9050 on Nexera X3) in DDA mode; feature extraction and alignment with Signpost MS; putative identification via LabSolutions Insight Explore™

Main Results and Discussion

Aroma profiling detected ~100 volatiles. PCA separated wild versus commercial strains along PC1. Wild Yeast 2 exhibited elevated p-vinylguaiacol, styrene and β-damascenone, correlating with sensory descriptors of spiciness. Targeted metabolomics identified 235 GC-MS and 104 LC-MS metabolites (total 278 unique compounds). PCA again distinguished wild and commercial yeasts, with inosine and hypoxanthine enriched in wild strains. Volcano plots revealed Wild Yeast 2’s high lactitol and maltose and low isoleucine and valine levels, suggesting enhanced yeast amino acid utilization. Non-targeted LC-QTOF analysis extracted over 4,300 features. PCA clustering mirrored targeted results. A commercial-strain marker (Compound A, m/z 193.0503) was annotated as ferulic acid via accurate mass, MS/MS fragment matching and database search (ChemSpider), confirming the workflow’s power for unknown compound attribution.

Benefits and Practical Applications

• Objective quantification of aroma and metabolite markers drives sensory-informed beer development
• Multimodal GC-MS and LC-MS coverage delivers a more complete metabolome
• Rapid, database-assisted identification accelerates troubleshooting in fermentation
• Insights into yeast nutrient uptake inform recipe adjustments (e.g., amino acid supplementation)
• Successful collaboration with a microbrewery yielded “KOCHO” Belgian IPA, optimized for balanced dryness and yeast-derived aroma

Future Trends and Potential Uses

Advances in ion mobility, high-resolution MS and integrated metabolomics software will further enhance unknown compound discovery. Expanding multi-omics packages to include sensory mapping and real-time fermentation monitoring can accelerate product innovation in craft brewing and broader food and beverage industries.

Conclusion

This study demonstrates a unified GC-MS/LC-MS multi-omics strategy for detailed aroma and metabolite analysis in craft beer. Combining targeted and non-targeted approaches with robust multivariate statistics and automated databases enables the rapid identification of flavor-defining compounds and informs practical brewing adjustments, culminating in the successful launch of a new IPA.

Reference

1) Shimadzu Corporation. Smart Aroma Database™ Ver. 2 and Smart Metabolites Database™ Ver. 2 Application News, 2024.
2) Shimadzu Corporation. Method Package for Primary Metabolites Ver. 3 Handbook, 2024.
3) Shimadzu Corporation. Pretreatment Procedure Handbook for Metabolites Analysis, 2024.