GC–MS and LC–MS Profiling Links Lager Chemistry to Craft Beer Consumer Preference

Beer is the world's most widely consumed alcoholic beverage, carrying deep cultural roots and enormous economic weight across the globe. While it is brewed from just four core ingredients, beer is home to a remarkably complex array of compounds that give rise to an equally wide range of flavors, from the crisp, clean taste of a classic lager to the bold, layered profiles of today's craft offerings. It is this diversity that has fueled a rapidly growing craft beer movement, attracting a new generation of drinkers who actively seek out beers with distinctive, intense flavors.

In response to this shift in consumer tastes, even the large, established breweries that built their reputations on mild, easy-drinking lagers are now experimenting with more flavor-forward styles. But what exactly is it that makes a beer appealing to someone who craves big, bold flavor? And how do brewers go about identifying and recreating the specific compounds responsible for that appeal?

These are the questions at the heart of a study that set out to bridge the gap between beer chemistry and consumer preference using a combination of cutting-edge analytical techniques, including gas chromatography and liquid chromatography mass spectrometry, to map out the chemical fingerprints of 18 different lager beers and connect them to what drinkers actually enjoy. To tell us more about this research and what it could mean for the future of brewing, LCGC International spoke with Devin Peterson, one of the researchers involved in the study and corresponding author of the resulting paper published in the Journal of Agricultural and Food Chemistry.¹

How would you combine gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–mass spectrometry (LC–MS) techniques to analyze both volatile and nonvolatile compounds in beer?

A comprehensive flavoromics strategy leverages the complementary strengths of GC–MS and LC–MS. GC–MS is well suited for the analysis of volatile and semi-volatile compounds, while LC–MS enables characterization of nonvolatile components.

In practice, the same sample is analyzed using parallel workflows, including headspace or extraction-based GC–MS methods and solid-phase extraction (SPE) for LC–MS profiling. Integration of data across these platforms allows for a more comprehensive identification of compounds contributing to the multimodal perception of flavor.

What is the role of gas chromatography–olfactometry (GC–O) in identifying key aroma-active compounds, and how does it complement traditional GC–MS?

GC–olfactometry (GC–O) provides a critical bridge between analytical chemistry and human perception by directly identifying odorants, including those present below instrumental detection limits. While GC–MS can identify volatile chemical constituents, it does not inherently indicate which compounds have odor properties or contribute to perceived flavor.

GC–O complements GC–MS by enabling trained panelists to detect odor events as compounds elute, allowing prioritization of odorants that are detectable by smell. However, detection by GC–O does not alone establish that a compound is odor‑active in the original sample, as contribution to flavor typically depends on its concentration relative to its odor threshold in the matrix.

How do you decide when to use a targeted vs. untargeted chromatography approach in food flavor analysis?

The choice depends on the research question. Untargeted approaches are valuable for discovery, as they capture a broad chemical space and can reveal novel or previously overlooked compounds that contribute to flavor. However, they may miss trace compounds that fall below analytical detection limits. Therefore, complementing these approaches with targeted MS/MS profiling of compounds identified through GC–O enables a more comprehensive analytical strategy.

What challenges arise when detecting trace-level (subthreshold) flavor compounds, and how can chromatography methods be optimized to capture them?

Trace-level compounds present challenges for MS detection due to low signal-to-noise ratios and potential co-elution in complex matrices such as beer. Despite their low abundance, these compounds can significantly influence flavor perception.

To address this challenge, the current study optimizes sample preparation through enrichment techniques (e.g., SPME or SBSE) and employs sensitive detection methods such as MS/MS. Instrumental sensitivity is complemented by sensory-guided prioritization to ensure that analytically minor compounds are not overlooked when they are sensorially important. Additionally, multidimensional GC or LC may be applied to further enhance compound separation and detection.

How would you design a workflow that integrates flavoromics data with sensory analysis using chromatographic techniques?

An effective workflow begins with comprehensive chemical profiling using GC–MS and LC–MS, complemented by targeted analysis of known flavor compounds identified through gas chromatography–olfactometry (GC–O). This combined approach enables investigation of a broad range of novel analytes to be investigated alongside known odorants.

Together, these methods support comprehensive characterization of beer by identifying both subthreshold and suprathreshold flavor compounds, as well as modulators that shape the sensory profile and influence consumer liking. Multivariate data analysis and statistical modeling approaches, such as partial least squares (PLS) regression and machine learning, are applied to relate chemical features to sensory perception, with sensory data (e.g., descriptive analysis or consumer testing) serving as the anchor.

A validation step is essential; recombination and omission experiments are conducted to confirm causal relationships. This integrated strategy enables a transition from correlation-based insights to a more mechanistic understanding of flavor.

What are the advantages of using GC-tandem mass spectrometry (MS/MS) over GC–MS in targeted flavor compound quantification?

GC–MS/MS offers enhanced selectivity and sensitivity compared to single quadrupole GC–MS and even time-of-flight GC–MS, making it particularly valuable for quantifying trace-level compounds in complex matrices. By using multiple reaction monitoring (MRM), background interference is reduced, enabling more accurate quantification.

This is especially important for compounds with low odor thresholds, where small concentration differences can have large sensory impacts. GC–MS/MS also increases confidence in compound identification, particularly in the presence of co-eluting species.

How can chromatographic methods help distinguish between flavor differences caused by raw ingredients vs. fermentation processes in beer?

Chromatographic techniques provide a means to differentiate flavor contributions from raw materials and fermentation while enabling tracking of precursor compounds and their transformation products. GC–MS is widely used to profile volatile compounds, including hop-derived terpenes, malt-derived Maillard products, esters, higher alcohols, and sulfur compounds. Complementarily, LC–MS characterizes nonvolatile constituents such as amino acids, phenolics, hop metabolites, and related reaction products.

Analysis of raw materials, wort, and samples collected throughout fermentation enables attribution of compounds to ingredient origin or yeast-driven formation. Time-resolved sampling provides insight into key biotransformation pathways, including conversion of hop-derived precursors into flavor compounds. When integrated with controlled brewing experiments and multivariate analysis, chromatographic profiling helps separate and quantify ingredient and process contributions, provides mechanistic insight into beer flavor development. In addition, isotopic labeling strategies, coupled with chromatographic analysis, enable direct tracing of precursor–product relationships and elucidation of flavor formation pathways.

What sample preparation techniques are important before running beer samples in LC–MS or GC–MS to ensure accurate results?

Sample preparation is critical for accurate and reproducible results. For GC–MS, techniques such as headspace (dynamic headspace or SPME) and liquid-liquid extraction are widely used to isolate volatiles while minimizing matrix interference. For LC–MS, solid-phase extraction and filtration are often necessary to reduce matrix effects and improve chromatographic performance.

Maintaining sample integrity is essential, maximizing stability, controlling temperature, and standardizing protocols all help ensure data quality and comparability.

How would you validate a chromatography-based method used to link chemical composition with consumer preference?

Validation requires demonstrating that the analytical method is robust, reproducible, and meaningfully linked to sensory outcomes. This includes traditional metrics (accuracy, precision, limits of detection/quantification), but also functional validation.

Recombination studies, where identified compounds are added back into a food matrix, are especially powerful, as are omission experiments to confirm the role of specific compounds. Ultimately, predictive models should be tested against independent datasets or consumer responses to confirm real-world relevance.

In a complex matrix like beer, how do you address co-elution and matrix effects when analyzing flavor compounds using chromatography?

Co-elution and matrix effects are persistent challenges in complex systems such as beer. These issues can be mitigated through optimized sample cleanup, improved chromatographic resolution (e.g., longer columns, column selection, or multidimensional separations), and the use of high-resolution MS and MS/MS fragmentation. Additional strategies include the use of isotopically labeled standards and software-based deconvolution techniques.

Importantly, combining orthogonal analytical approaches and integrating sensory data helps ensure that analytical artifacts do not mislead interpretation.

References

1. Borcherding, J.; Booth, M.; Uribe, S. T. et al. Volatile and Nonvolatile Contributors to Lager Beer Acceptability in High-Flavor-Liking Consumers. J Agric Food Chem 2026.DOI: 10.1021/acs.jafc.5c16579