3.1. Consumer Study
Of the 105 consumers, 60.2% were male and 39.8% were female. Participant ages ranged from 20 to 78 years, with 27.4% being under 30 years old, 15.0% over 55 years old, and 57.5% aged between 30 and 55 years. To participate in the study, consumers were required to be at least occasional Sherry wine drinkers, a criterion met by 55.4% of the participants. Among the remaining participants, 24.6% reported consuming Sherry wine occasionally during the month, 13.8% several days a week, and 6.2% daily. Prior to the sensory sessions, participants completed a screening questionnaire designed to collect information on specific food aversions or strong individual preferences (neophilias), ensuring that candidates with extreme pre-existing biases that could alter, skew, or confound the pairing evaluations were excluded. Additionally, candidates reporting food allergies, medical conditions incompatible with alcohol consumption, or pregnancy were excluded from participation.
The purpose of this tasting session was to evaluate consumer perception through two distinct methodological approaches: subjective hedonic liking (evaluated via a Likert scale) and conceptual pairing appropriateness or degree of fit (evaluated via the Linking method). Identifying which combinations generated the best and worst evaluations across both dimensions was crucial, as these specific pairings would then be selected for further investigation with the expert consensus group to uncover the underlying drivers of pairing success.
By utilizing the “SensoGraph” application, the results of the Linking test (focusing on perceived pairing appropriateness and harmony) were obtained and processed (
Figure 1). The preferred pairings were: PX wine with chocolate, vanilla custard, blue cheese, foie gras toast with mango chutney, and lemon sorbet; Oloroso with blue cheese, grilled meat, foie gras toast with mango chutney, boiled prawns, and stewed meat; and Fino with boiled prawns, seasoned potatoes, grilled meat,
salmorejo, and smoked salmon. Conversely, the lowest-rated pairings were: PX with olives, salmon, grilled meat, and boiled prawns; Oloroso with lemon sorbet, pickled gherkins, and olives; and Fino with pickled gherkins, chocolate, and vanilla custard.
Regarding the Likert scale test (measuring individual hedonic acceptance), the comprehensive dataset is displayed in
Figure 2. While acceptance patterns for Fino and Oloroso wines were highly similar, the pattern for PX was markedly distinct. Model analysis confirmed that the random effect of the consumer is highly significant (
p < 0.001), fully justifying the adoption of the mixed model. The wine factor (
p = 0.696) was not significant. Regarding the dish factor (
p < 0.001), pairings with pickled gherkins received the lowest ratings, while those with foie gras toast with mango chutney were the most appreciated; a significant difference was found between these two, but not when compared to most of the remaining dishes. As expected, the wine x dish interaction (the pairing itself) was confirmed to significantly influence (
p < 0.001) the consumers’ hedonic evaluation. Therefore, the highest-rated pairings in the Likert test were: PX wine with chocolate, vanilla custard, foie gras toast,
Manchego cheese, and blue cheese; Oloroso with grilled meat, foie gras toast, boiled prawns, and blue cheese; and Fino with grilled meat, boiled prawns, seasoned potatoes, and olives. The lowest-rated pairings included: PX wine with olives, vanilla custard, pickled gherkins, and lemon sorbet; Oloroso with pickled gherkins, lemon sorbet, vanilla custard, and chocolate; and Fino with chocolate, vanilla custard, pickled gherkins, and lemon sorbet.
As can be observed, the outcomes from both methodologies (hedonic acceptance and conceptual appropriateness) are highly consistent. However, the Linking method proved simpler to implement and required less data processing, resulting in a faster response time.
Based on these findings, our objective was to maximize the signal-to-noise ratio in order to clearly identify the key chemical markers (volatiles) and sensory descriptors that drive strong harmony or disharmony in Sherry wine pairings, avoiding the confounding noise typically associated with intermediate or neutral samples. To achieve this, the dishes representing both the highest- and lowest-rated pairings (across both hedonic and appropriateness criteria) for each wine type were selected for the subsequent phase of the study: Manzanilla olives, grilled meat, dark chocolate, foie gras toast with mango chutney, boiled prawns, pickled gherkins, blue cheese, and lemon sorbet. These selected foods were then analyzed via gas chromatography and subjected to sensory analysis by the expert consensus group.
3.2. Analytical Sensory Evaluation by an Expert Consensus Group
Table 2 summarizes the group’s evaluations of the dishes selected in the previous phase of the study across a series of taste attributes (sweetness, acidity, bitterness, saltiness, umami), aromatic attributes (intensity, persistence, and spiciness), and texture attributes (fatty character and body). As a measure of reproducibility, standard deviations were calculated for both intra-taster repeatability (repeated measurements) and inter-taster reproducibility (panel). In both cases, the deviations were generally low, demonstrating an acceptable level of agreement.
Similarly, the group evaluated the three wines (Fino, Oloroso, PX) based on a set of sensory attributes ranging from basic tastes (sweetness, acidity, bitterness, saltiness, umami) to more complex dimensions related to their structure (alcohol, body) and aromatic expressiveness (intensity, persistence, and spiciness), as shown in
Table 3. These data systematically characterize the sensory profile of each food and wine, serving as the foundation for the subsequent pairing analysis.
Furthermore, the tasters provided an overall score for each of the pairings (
Table 4). A Partial Least Squares (PLS) regression analysis was applied for each wine, using the sensory descriptors of the dishes as predictor variables. The data for the fitted models are presented in
Table 5.
The results of the fitted models reflect an excellent descriptive capacity for all three wine types, with remarkably high R2 values (ranging from 0.965 to 0.997). This indicates that the sensory descriptors of the dishes explain nearly the entirety of the pairing quality. Likewise, the Root Mean Square Error (RMSE) values, which are lower than the standard deviations of the dependent variable “Overall Pairing Score,” confirm the precision of the model in describing the observations. However, rather than the quantitative models themselves, the value of these results lies in interpreting the role of the distinct dish descriptors in their pairing with each wine.
For Fino wine, its minimal residual sugar content (<1 g/L) and clean organic acid profile (volatile acidity < 0.25 g/L) explain its strong positive association with saltiness (VIP = 1.572, r = 0.557) and umami (VIP = 1.762, r = 0.634). This reflects a classic taste enhancement mechanism, where the dry, saline character of biological aging synergizes with umami matrices. Conversely, the complete absence of residual sugar illustrates the severe taste contrast observed with sweet dishes (VIP = 1.346, r = −0.435), which strip the wine of its delicate fruitiness. Furthermore, excessive persistence of the dish could unbalance the combination (perhaps due to masking the Fino wine) as indicated by its negative correlation.
In the case of Oloroso wine, the driver for pairing success is heavily rooted in umami (VIP = 1.352, r = 0.753) and body (VIP = 1.022, r = 0.575). This is physically driven by texture–alcohol lipid cleavage: the elevated ethanol content (18% ABV, the highest among the studied wines) and extended oxidative aging (6 years) effectively dissolve the lipid coating of protein-rich foods (e.g., grilled meat or foie gras), clearing the palate while its glyceric body balances heavy textures. On the other hand, the penalty imposed by dish acidity (VIP = 1.557, r = −0.593) highlights a taste imbalance, as low-acid oxidative wines fail to buffer highly acidic ingredients (e.g., pickled gherkins), resulting in organoleptic discordance.
Finally, Pedro Ximénez (PX) pairings showcase both trigeminal and cognitive pairing mechanisms. The positive influence of sweetness (VIP = 1.346, r = 0.655) and spicy character (VIP = 1.094, r = 0.479) points to trigeminal suppression, where the high viscosity and sugar concentration of PX coat the oral mucosa, dampening the pungency of spices while providing a harmonious mouthfeel. Furthermore, the strong acceptance of PX with desserts or dark chocolate likely incorporates cultural and cognitive expectations of sweet-with-sweet pairings, whereas its antagonism toward saltiness (VIP = 1.441, r = −0.673) underscores the physical limits of high-viscosity sweet wines when contrasting with sharp saline matrices.
3.4. Analysis of Pairings Based on Volatile Content
Table 6 details the volatile compounds with the highest relative areas that matched within the analyzed wine and gastronomic product pairs. The results obtained from the hedonic test reveal that the quality of a pairing is not solely determined by the absolute number of shared molecules, but rather by the chemical nature and actual sensory impact of these compounds. Consequently, the application of Chartier’s Theory [
7] is nuanced by its alignment with the sensory matrix of the dish and the relative intensity of the molecules.
The study identified cases where a high molecular overlap translated into excellent sensory evaluation, confirming the existence of potential chemical correspondences:
For example, Pedro Ximénez and Chocolate (score 9.8,
Table 4) displays an exceptional affinity based on the furan family (furfural, 5-methylfurfural), which are linked to sweet and roasted notes [
33,
34]. The perceptual relevance of the pairing is ensured by compounds with low detection thresholds, such as ethyl octanoate (0.005 mg/L), and ethyl hexanoate (0.014 mg/L) [
11]. The synergy between caramelized notes and fruity and fatty sensations accounts for its high acceptance. Another example is Fino wine and Boiled prawns (score 9.6,
Table 4), where the shared presence of medium-chain esters, such as ethyl hexanoate, ethyl decanoate, and isoamyl acetate, establishes a fruity and fresh chemical correspondence that complements the crustacean’s lipid profile. Concurrently, the convergence of thermal and oxidative furanic compounds (furfural and furfuryl alcohol), arising from Maillard reactions during cooking and yeast autolysis during Fino’s biological aging, along with 2,6-dimethylheptan-4-one, generates a synergistic resonance of toasted and balsamic notes.
Despite the importance of molecular overlap, the analysis detected instances where an abundance of common volatiles did not prevent negative evaluations due to sensory conflicts. The Fino–Chocolate pairing illustrates how the wine’s fruity esters fail to harmonize with the roasted notes of cocoa, creating an unappealing contrast. Similarly, combinations with high molecular overlap, such as Oloroso–Chocolate or PX–Boiled prawns, were poorly rated by the expert consensus group, reinforcing that the specific aromatic character and its interaction with the food matrix are more critical than the mere quantity of shared compounds. In the case of Pedro Ximénez–Olives, the co-occurrence of furfural and acetic acid was insufficient to offset the opposition between the extreme sweetness of the wine and the saline and bitter profile of the olives. This negative contrast is driven by in-mouth gustatory perceptions rather than purely orthonasal aroma interactions; indeed, sensory analysis concluded that Fino pairs poorly with sweetness and is disadvantaged by high dish persistence, whereas PX displays a strong taste incompatibility with high saltiness.
An analysis of variance was performed on the relative areas of each of the 134 compounds identified in the eight dishes, taking the quality of the pairing with each wine (good, medium or bad) as the factor of variation and all the descriptors employed in the discussion were obtained from verified flavor databases [
33,
34].
In the pairings with Fino wine, only 12 compounds presented a p < 0.05, among which 3-methyl-1,2-cyclopentanedione (with toasted and sweet notes) and phenethyl alcohol (floral and sweet) confirmed a negative correlation; that is, the greater the amount of the compound in the dish, the worse its pairing with Fino was rated. On their part, compounds such as isoamyl alcohol (fermentation), 2,6-dimethylheptan-4-one (fruity and sweet), and α-terpinolene (citric) showed a positive but non-linear correlation, with a maximum rating at the intermediate concentration, as if an excess concentration penalized the evaluation. From these data, it could be deduced that Fino wine can accompany dishes of limited aromaticity well, provided that their most characteristic notes are not sweet and/or toasted.
In the pairings with Oloroso wine, there were 25 volatile compounds that presented some statistical significance between the categories (p < 0.05), all of them being negatively correlated with the quality of the pairing. Some of these compounds are characterized by toasted, sweet, woody, or spicy notes, but the most recurrent aromatic notes are balsamic, herbaceous, fruity, floral, and citric, which are characteristic of compounds such as 2-carene; geranyl acetate; 2-nonanone; α-terpinene; α-pinene; α-curcumene; β-bisabolene; β-myrcene; camphor; phenethyl acetate; camphene; cis-β-ocimene; fenchyl alcohol; limonene; γ-hexalactone; γ-elemene; linalool; and nerol. According to these data, it could be hypothesized that Oloroso wine does not accompany dishes with a broad and fresh nose well.
Regarding the pairings with PX wine, three compounds showed a positive correlation with the quality of the pairing (p < 0.05). The interaction of 3-methyl-1,2-cyclopentanedione (toasted, sweet, and present in the PX wine) and phenethyl alcohol (floral, sweet) in the pairing with PX is highly positive, precisely the opposite of what occurred with Fino wine, as previously explained. On the other hand, the compounds nonanal (citric), isoamyl alcohol (fermentation), and 2,6-dimethylheptan-4-one (fruity) presented a negative correlation with the quality of the pairing with PX (p < 0.05). From all of this, it could be deduced that a dish characterized by sweet and/or toasted notes, far removed from any sensation of freshness, is associated with a good pairing with this wine. And in this sense, it is interesting to specify that nine of the 28 compounds identified in the PX wine are defined by toasted, caramel, or sweet aromatic notes.