The influence of storage conditions on the chemistry and flavor of hoppy ales.

Understanding the factors which lead to the (in)stability of the chemistry and sensory of hoppy beer styles such as India Pale Ales (IPAs) has become a major concern for many brewers. Therefore, the evolution of several volatiles under different storage conditions (room temperature, cold storage, forced aging) was investigated in eleven hoppy ales and one lager which were commercially produced in Germany. Compared to the lager, the fresh ales contained higher initial aldehyde levels. Furthermore, the distribution of lipid oxidation and Maillard reaction products differed from those typically found in lager beer. Upon storage, significant increases of some staling aldehydes were observed. Interestingly, the concentrations of some hop aroma volatiles like terpenoids (i.e. linalool and geraniol) were relatively stable throughout storage and counteracted "oxidized" impressions in ales high in these compounds. In comparison, hop aroma in some ales was driven by less stable volatiles such as esters.

Evaluation of Variety, Maturity, and Farm on the Concentrations of Monoterpene Diglycosides and Hop Volatile/Nonvolatile Composition in Five Humulus lupulus Cultivars.

Pentose-hexose monoterpene alcohol glycosides were isolated and semiquantitatively measured in dried Humulus lupulus cones using UHPLC-qTOF-MS/MS and HPLC fractionation followed by GC-MS. The samples evaluated included hop cones from five important dual-purpose cultivars (varieties) in the United States, from two locations (farms) per variety and from three distinct harvest time points (maturities) per location, as dictated by dry-matter (% w/w) at the time of harvest. Hop variety accounted for the biggest variation among the concentrations of pentose-hexose monoterpene alcohol glycosides as well as other volatile and nonvolatile chemical factors measured in the samples. This indicates that genetics plays a major role in hop flavor production. Interestingly, "maturity", or ripeness at the time of harvest, was the next most significant factor impacting the concentrations of pentose-hexose monoterpene alcohol glycosides along with most of the other volatile and nonvolatile factors (such as total oil concentration and composition). However, maturity notably had a bigger impact on some cultivars such as Sabro, Mosaic, Simcoe, and Citra. Surprisingly, farm (i.e., location, farming practices, etc.) accounted for the least amount of variation among the concentrations of the different analytical factors. These results highlight the importance of breeding/genetics as well as considering hop maturity/ripeness at the time of harvest on the production and subsequent development of analytical chemical factors associated with driving hoppy beer flavor. It is essential for future studies assessing the impact of different farming practices and locations (i.e., regionality, terroir, etc.) on the constituents in hops important for hoppy beer flavor to consider and account for the impact of hop maturity as well as genetics.

Evaluating the Chemical Components and Flavor Characteristics Responsible for Triggering the Perception of "Beer Flavor" in Non-Alcoholic Beer.

Forty-two commercial non-alcoholic beer (NAB) brands were analyzed using sensory and chemical techniques to understand which analytes and/or flavors were most responsible for invoking the perception of "beer flavor" (for Northern Californian consumers). The aroma and taste profiles of the commercial NABs, a commercial soda, and a carbonated seltzer water (n = 44) were characterized using replicated descriptive and CATA analyses performed by a trained sensory panel (i.e., 11 panelists). A number of non-volatile and volatile techniques were then used to chemically deconstruct the products. Consumer analysis (i.e., 129 Northern Californian consumers) was also used to evaluate a selection of these NABs (i.e., 12) and how similar they thought the aroma, taste and mouthfeels of these products were to beer, soda, and water. The results show that certain constituents drive the aroma and taste profiles which are responsible for invoking beer perception for these North American consumers. Further, beer likeness might not be a driver of preference in this diverse beverage class for Northern Californian consumers. These are important insights for brewers planning to create products for similar markets and/or more broadly for companies interested in designing other functional/alternative food and beverage products.

Analysis of Hop-Derived Thiols in Beer Using On-Fiber Derivatization in Combination with HS-SPME and GC-MS/MS.

The quantitation of the hop varietal thiols 4-mercapto-4-methyl-2-pentanone (4MMP), 3-mercapto-1-hexanol (3MH), and 3-mercaptohexylacetate (3MHA) from beer is challenging. This primarily relates to their low concentration (ng/L levels) and their reactivity. Published assays for thiol quantitation from beer include complex and/or time-consuming sample preparation procedures involving manual handling and use reagents that are harmful because they contain mercury. To facilitate thiol analysis from beer, the current article is concerned with the implementation of an automated headspace solid-phase microextraction (HS-SPME) on-fiber derivatization (OFD) approach using 2,3,4,5,6-pentafluorobenzyl bromide followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Optimization of HS-SPME and MRM conditions was based on a central composite design approach. The final OFD-HS-SPME-GC-MS/MS method yielded limits of quantitation below the sensory thresholds of 4MMP, 3MH, and 3MHA. Method validation and application on beers brewed with German, Australian, and US hops, as well as with added fruits displayed excellent method performance.

Characterizing Volatile and Nonvolatile Factors Influencing Flavor and American Consumer Preference toward Nonalcoholic Beer.

In this study, the chemical and sensory profiles of 42 different nonalcoholic beer (NAB) brands/styles already on the global market and produced through several different brewing techniques were evaluated. A trained panel (i.e., 11 panelists) performed standard-driven descriptive and check-all-that-apply analyses in triplicate to sensorially characterize the aroma and taste/mouthfeel profiles of 42 commercial NABs, a commercial soda, and a commercial seltzer water (n = 44). These beers were also chemically deconstructed using several different analytical techniques targeting volatile and nonvolatile compounds. Consumer analysis (n = 129) was then performed to evaluate the Northern Californian consumer hedonic liking of a selection (n = 12) of these NAB brands. These results provide direction to brewers and/or beverage producers on which techniques they should explore to develop desirable NAB offerings and suggest chemical targets that are indicators of specific flavor qualities and/or preference for American consumers.