The fan community for non-alcoholic beer is growing rapidly. The alcohol-free barley juice with the edge in the market will always be the one which customers prefer. Many still favor beer-like beverages with a flavor of real beer, i.e., that doesn’t exhibit flavor deficiencies following the alcohol withdrawal. However, the dealcoholizing process leads to loss of volatile organic compounds (VOCs) that contribute to the overall beer flavor. VOC loss therefore affects the quality and flavor profile of alcohol-free and alcohol reduced beers. 

Challenge: 

When compared to the real thing, non-alcoholic beer has lower concentrations of isoamyl acetate, esters, alcohols, fatty acids, and phenolic compounds. Those compounds are important for the characteristic beer aroma. How then can the flavor difference best be characterized in terms of both profile and individual compound contributions? 

Solution: 

To answer that question, GERSTEL application experts Megan C. Harper, Nicole Kfoury and Jackie Whitecavage combined olfactory and instrumental analysis. Tools of the trade were the GERSTEL Olfactory Detection Port (ODP 4) combined with a GC-MS system (8890 GC with 5977B inert plus MSD, both from Agilent Technologies) fitted with a GERSTEL Thermal Desorption Unit TDU 2. By using olfactory detection in parallel with MS, odor-active compounds can be found and identified. It can be determined which compounds contribute to the flavor and where the differences lie between regular and non-alcoholic beers.

Detail: 

To determine flavor differences caused by de-alcoholization or by alcohol reduced brewing, a maximum of flavor and aroma compounds had to be extracted from the beer and beer-like matrix and determined. Harper, Kfoury, and Whitecavage combined two powerful extraction techniques: Stir Bar Sorptive Extraction (SBSE) based on the GERSTEL PDMS TwisterTM and thin film solid phase microextraction (TF-SPME). Both techniques have proven their worth for determination of flavor and odor active compounds in complex samples.

Conclusion: 

The combination of SBSE and TF-SPME enabled highly efficient extraction and concentration of key flavor compounds from regular and non-alcoholic beers. As the authors report in GERSTEL AppNote 250, simultaneous use of the two extraction techniques resulted in excellent recovery of a broad spectrum of analytes that could subsequently be determined by Thermal Desorption(TD)-GC-MS/O.  Detailed aroma profiles of the beverages were established using the ODP. The obtained data reflect differences in concentrations, loss of esters and the presence of “new” compounds in non-alcoholic beers, i.e., additives or compounds formed in process related Maillard reactions. Last, but not least, the GERSTEL ODP was the tool that enabled the identification of key sensory active components, even those at ultra trace level. This knowledge is valuable for product evaluation and product development helping brewers in their work to achieve higher customer satisfaction and loyalty in the hard fought over marketplace of alcohol-reduced beer products. (GD)

Literature Reference 

Haper MC, Kfoury N, Whitecavage (2023), Volatile Organic Compound and Sensory Pro-files of Alkoholioc versus Non-Alkoholic Beer Using Immersive Twister and TF-SPME Extraction, GERSTEL AppNote 250