Tracing the origin of Argentine Malbec wines by sensometrics.

The study of terroir, increasingly popular in scientific circles, remains a challenging field, particularly in terms of sensory analysis. This paper summarizes our own contribution to the field-an approach for tracing the typicity of wines by sensometrics, using the Malbec variety as a case study. This large-scale research fingerprinted 81 wines from 29 parcels from highly contrasting environments (varying climate, elevation, and soils), produced under standardized conditions in three consecutive vintages. Wines were evaluated through descriptive sensory analysis (DA) by a trained panel, and sensory descriptors were associated with different size geographic scales (zones, departments, and Geographic Indications (GIs)). The application of different sensometric tools allowed us to describe the typicity of wines and discriminate each region, proposing a novel methodology for the comprehensive evaluation of terroir from a sensory viewpoint. The vintage effect was very strong at the departmental and GI level, with aroma, taste and mouthfeel descriptors varying annually. However, certain origin descriptors remained consistent, providing insight into the typicity of Malbec. Considering the extension of the experimental study performed, this methodology provides a proof of concept for understanding both terroir and vintage effects from a sensorial perspective, offering wine producers and consumers a clear message backed by scientific evidence.

Wine Closure Performance of Three Common Closure Types: Chemical and Sensory Impact on a Sauvignon Blanc Wine.

A Napa Valley Sauvignon blanc wine was bottled with 200 each of a natural cork, a screw cap, and a synthetic cork. As browning is an index for wine oxidation, we assessed the brown color of each bottle with a spectrophotometer over 30 months. A random-effects regression model for longitudinal data on all bottles and closure groups found a browning growth trajectory for each closure group. Changes in the wine's browning behavior at 18 months and 30 months showed that the browning of the wine bottles appeared to slow down later in the storage period, especially for natural corks. The between-bottle variation was the highest for the natural cork. At 30 months, we separated the bottles by the extent of browning and samples were pulled from the high, mid, and low levels of browning levels for each closure. The degree of browning is inversely correlated with free SO2 levels ranging from 5 to 12 mg/L. However, a Quantitative Descriptive Analysis (QDA™) sensory panel could not detect any difference in their aroma and flavor profile between closure types regardless of browning level. Even low levels of free SO2 retain protection against strong oxidation aromas, and visual browning detected by spectrophotometer seemed to precede oxidative aroma and flavor changes of the aging Sauvignon blanc.

Investigation of Different Winemaking Protocols to Mitigate Smoke Taint Character in Wine.

There is an increase in the levels of volatile phenols in wine made with smoke-impacted grapes. These compounds are present in wood smoke resulting from the pyrolysis (thermal decomposition) of lignin and at high levels give overpowering smoky and ashy characters to a wine. This research aimed to compare all the suggested wine mitigation strategies that evolved from prior research using smoke-impacted grapes under identical winemaking conditions except for the parameter under investigation. Cabernet Sauvignon grapes were received from three areas with varying amounts of smoke exposure in Northern California. Gas chromatography combined with mass spectrometry (GC-MS) and descriptive analyses were performed to correlate the volatile phenol composition to smoke taint characteristics. The winemaking variables investigated were the use of different fermentation yeasts, oak additions, and fermentation temperatures. Among other attributes, smokiness and ashy aftertaste were significantly different among the wines, showing a clear difference between the wines made from smoke-impacted fruit and the control wines made from non-impacted fruit. Findings indicate that mitigation strategies during red wine fermentation have a limited impact on the extraction of smoke-taint markers and the expression of smoke-taint sensory characteristics.

Characterizing the chemical and sensory profiles of traditional American meads.

The compositional and sensorial profiles of traditional American meads were determined using standard enological, volatile, and descriptive analyses. Forty-one commercial meads produced by 35 meaderies across 20 states were selected to encompass a broad product range. The meads were analyzed for ethanol content, residual sugar, pH, titratable acidity, acetic acid, and free and total sulfur dioxide. Forty-three volatile compounds (alcohols, esters, acids, terpenes, aldehydes, aromatic hydrocarbons, etc.) were tentatively identified using a nontargeted HS-SPME-GC-MS method. Ethyl octanoate, phenylethyl alcohol, ethyl decanoate, and ethyl acetate were the most relatively abundant volatile compounds across the sample set. A trained panel (n = 11) evaluated each mead using descriptive analysis and the chemical and sensory analyses were compared. Acidity, sweetness, and cloying and viscous mouthfeel sensations, and alcoholic heat were the most influential sensory attributes and were driven by titratable acidity, residual sugar, and ethanol content, respectively. Ethyl octanoate and ethyl decanoate were correlated with manure aroma, phenylethyl alcohol with yeast and green aromas, and ethyl acetate with citrus, solvent, and green olive aromas. This research further elucidates the empirical relationship between the chemical composition and sensory profiles of commercial meads. PRACTICAL APPLICATION: This work provides the mead industry with further understanding of the compositional drivers of the sensory profiles of commercial meads and demonstrates product categories (dry, semi-sweet, sweet) do not necessarily indicate compositional or sensory attributes.

Investigating the impact of regionality on the sensorial and chemical aging characteristics of Pinot noir grown throughout the U.S. West coast.

The sensorial and chemical differences among Pinot noir wines from different vineyard locations were investigated. Grapes of a single Pinot noir clone were grown on twelve different vineyard sites along the U.S. West Coast. Wines from a single vintage (2015) were made using a standardized protocol and equipment. Sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences were observed among these wines at two aging time points (8- and 20- months). Vineyard location (i.e. latitude and longitude) was one of the main factors describing the major differences between the wines, while other details (i.e. soil type (60 cm), rootstock age, soil pH, rootstock type, and vines/acres) were possibly important for defining unique aging characteristics of certain vineyards. Overall, single clone Pinot noir grapes grown in different regions but made under standardized winemaking produced wines with unique chemical and sensorial profiles, which generally persisted throughout aging.

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.

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.

Evaluation of the Intrinsic and Perceived Quality of Sangiovese Wines from California and Italy.

Sangiovese is the most cultivated red grape variety in Italy where it is certified for the production of several Protected Designation of Origin (PDO) wines, and it is one of the most cultivated Italian red grape varieties in California. Despite the global distribution of this variety, there is a lack of international studies on Sangiovese grapes and wines. For this reason, the present study aimed to compare 20 commercial Sangiovese wines from 2017 harvest, 9 produced in Italy (Tuscany) and 11 in California, in order to evaluate the intrinsic and perceived quality. The eligibility, identity, and style properties (the intrinsic quality) of the wines were evaluated. A group of 11 Italian experts evaluated the perceived quality by rating the typicality of the wines. The experimental data showed that the intrinsic quality of Sangiovese wine samples was affected by the growing area; in particular, the wine resulted very different for the color indices and polyphenol composition. The above differences in intrinsic quality levels did not lead to a different evaluation of the perceived quality (typicality) by the wine experts. The results evidenced that Sangiovese variety is recognizable also if grown outside its original terroir, and fresh and fruity wines were considered more typical. This study expands our current knowledge of Sangiovese wines and the contribution of regional characteristics to the composition of wine.

Effect of metal chelators on the oxidative stability of model wine.

Oxidation is a major problem with respect to wine quality, and winemakers have few tools at their disposal to control it. In this study, the effect of exogenous Fe(II) (bipyridine; Ferrozine) and Fe(III) chelators (ethylenediaminetetraacetic acid, EDTA; phytic acid) on nonenzymatic wine oxidation was examined. The ability of these chelators to affect the formation of 1-hydroxyethyl radicals (1-HER) and acetaldehyde was measured using a spin trapping technique with electron paramagnetic resonance (EPR) and by HPLC-PDA, respectively. The chelators were then investigated for their ability to prevent the oxidative loss of an important aroma-active thiol, 3-mercaptohexan-1-ol (3MH). The Fe(II)-specific chelators were more effective than the Fe(III) chelators with respect to 1-HER inhibition during the early stages of oxidation and significantly reduced oxidation markers compared to a control during the study. However, although the addition of Fe(III) chelators was less effective or even showed an initial pro-oxidant activity, the Fe(III) chelators proved to be more effective antioxidants compared to Fe(II) chelators after 8 days of accelerated oxidation. In addition, it is shown for the first time that Fe(II) and Fe(III) chelators can significantly inhibit the oxidative loss of 3MH in model wine.