Correlation of Chemical and Sensory Data to Track Aging of an American IPA Beer at Different Storage Temperatures

Importance of the topic

Beer shelf stability is critical for maintaining product quality and consumer satisfaction. Changes in aroma compounds during storage can diminish flavor and reduce brand consistency. Combining sensory panel data with comprehensive aroma profiling allows manufacturers to monitor and extend shelf life.

Objectives and Study Overview

This study evaluated the effect of storage temperature on the aroma profile and perceived freshness of an American IPA over a ten week period. Samples were stored at refrigeration and room temperatures and analyzed at multiple time points using sensory evaluation and non-targeted chemical profiling.

Methodology and Instrumentation

• Sample Collection: Bottles were filled on the brewery line and stored for 0, 1, 2, 4, and 10 weeks at 34–36°F (cold) and 68–70°F (warm).
• Sensory Analysis: A trained panel of five tasters scored freshness on an 0–8 scale where 8 indicates full flavor and 0 indicates non-consumable.
• Chemical Analysis: Headspace solid phase microextraction with a DVB/CAR/PDMS fiber was used. Extraction at 35°C for 20 minutes followed by 3 minute desorption in a 250°C inlet.
• Gas Chromatography and Mass Spectrometry: Agilent 7890 GC with Stabilwax column temperature ramp from 40°C to 250°C, helium carrier at 1.4 mL/min, coupled to LECO Pegasus BT time-of-flight MS (mass range 33–500 m/z, 10 spectra per second).
• Data Processing: ChromaTOF software for peak finding and deconvolution, NIST library and retention index matching, and PCA in MatLab.

Main Results and Discussion

• Sensory Scores: Freshness declined over time. Room temperature samples showed significant aging after one week, while refrigerated samples retained freshness up to four weeks.
• Chemical Observations: Deconvolution resolved coeluted compounds such as isobutyl acetate (stable) and alpha-pinene (declining). Over 350 volatile analytes were tracked.
• Compound Trends: Terpenes and esters that contribute fruity and pine notes decreased with age; Maillard products and Strecker aldehydes increased, especially at higher temperatures.
• Multivariate Analysis: PCA scores correlated strongly with sensory scores, confirming that the main chemical variations align with perceived freshness.
• Correlation Analysis: A set of 36 analytes negatively or positively correlated with sensory scores, enabling targeted markers for beer aging.

Benefits and Practical Applications

Integrating sensory evaluation with non-targeted GC-TOFMS profiling provides a robust approach for monitoring beer quality. Identifying specific chemical markers supports quality control, shelf life prediction, and formulation adjustments.

Future Trends and Potential Applications

• Extension to other beverages and food products for comprehensive shelf life studies.
• Use of advanced deconvolution algorithms and high resolution MS for deeper profiling.
• Integration with predictive modeling and artificial intelligence for real-time quality monitoring.

Conclusion

The combined sensory and chemical analysis demonstrated that storage temperature accelerates flavor loss in beer. Non-targeted aroma profiling, supported by PCA and correlation analysis, can effectively track aging markers and guide strategies to improve shelf stability.