The results of the present study, conducted with a range of sparkling wines, suggests that people, no matter whether they are expert Champagne tasters, expert wine tasters, or simply social drinkers, are unable to reliably determine the proportion of white Chardonnay grapes in the sparkling wines when tasted blind. We found that dosage and alcohol content are attributes that tasters actually rely on when judging the contribution each grape type makes to the distinctive flavour of a sparkling wine.
Our findings are in line with those studies of still wine that have investigated the ability of people (experts and non-experts) to sort wines in terms of the characteristics coming from the grape (that is, the ‘primary aromas’,) rather than properties of the wine added by vinification, bottle fermentation, lees contact (amount of time the bottle-fermented wine is left in contact with the dying yeasts before disgorgement when the yeast deposits are removed and the wine is re-corked), and elevage (the process of maturing the base [still] wine in oak barrels), or extrinsic cues from branding and labelling [13–15]. These results add to the literature on the blind tasting of sparkling wines [1, 8] suggesting that this extrinsic information might contribute to what people report as being the characteristic tastes (or qualities) of certain varieties of sparkling wine.
However, the sparkling wines in this study did not vary along a single dimension. In addition to variations in the proportion of white grapes, they were also different in terms of the place the wine came from, as well as its vintage, quality, alcohol content, and dosage. These various factors introduce further complexity to the tasters’ task, but at the same time make the testing/tasting situation more realistic. Still, future experiments could test an expert’s ability to make finer grain comparisons of wines (for example, from the same vintage, or different cuvées or vintages from the same Champagne house, or sort white grape-only wines from different regions - see ). A skilful chef de cave might be able to discover, after experimenting with particular blends, the difference each component makes to the overall well-integrated flavour of the Champagne.
Although the results show that experienced Champagne drinkers are not able to judge the contribution of each grape variety to the flavour of a Champagne, tasters certainly recognised differences between the wines and rated them differently. It would therefore be wrong to infer from the fact that tasters cannot perceive the difference that the proportion of the various grape varieties makes to the blend, that it did not make a difference to the resulting flavour of the blend. Instead, we hypothesise that success in blending has made it more difficult for tasters to identify the particular contributions made by each grape variety to the overall flavour profile. This suggests another intriguing possibility worthy of further investigation: Whether complexity might be more easily recognised than the actual components in the wine. In support of this point, we found that Perriet Jouet Belle Epoque Blanc de Blanc was correctly identified as a non-blend by nine tasters (five were correct, while another four people guessed it was a Blanc de Noir; see Figure 1). Other samples were speculated to be non-blends by at most three tasters. It would be interesting for future studies to compare the perceptual heuristics applied to simplicity versus complexity in blended and non-blended wines.
Another interesting result to emerge from the present study is the fact that there was no correlation between the objective price of the bottles and our participants’ preference ratings for the sparkling wines tasted blind. This replicates previous results , and extends them over a much wider price range (€11 to €23 in Lange et al.; £18 to £400 here). A lack of correlation between preference and price fits with the much larger body of research on still wines (see  for a review). We would also like to suggest, as an area for future research, that this effect might be different for experienced tasters as compared to social drinkers. Based on these results, we suggest that more expensive champagnes, with attributes related to ageing, might only be appreciated by expert tasters who are more likely to have previously experienced such flavour profiles.
Were the self-declared expert Champagne tasters in the present study a representative sample? Of course, with more expert tasters some tests would have been more powered and certain of the null results might have reached significance (for example, with about 15 experts reporting in the same way as the four that were tested here, there would be enough power to reliably conclude that experts estimate the Blanc de Blanc as having more Chardonnay than the Blanc de Noir). However, such a large sample of expert Champagne drinkers might not be possible outside the region. Instead, as described in the Methods section, all the participants tested in this study had professional activities related to wine or spirits, including the novice and intermediate Champagne tasters. Some of those that self-assessed themselves as expert Champagne tasters were writers and journalists on the topic (note that previous verbalization of characteristics of wines tasted may have affected their taste perception [16, 17]), while others indicated that they were wine merchants. The individuals we tested are likely to have had significantly more experiences and exposure to Champagne than those tested in previous research [1, 8], making these results highly novel. The high baseline of tasting knowledge across the whole sample is demonstrated by the lack of correlations between the sweetness and fruitiness ratings for the wines. Using a lack of correlation between perceptually ‘similar’ attributes might provide an independent means of categorizing people as expert or non-expert tasters in future research.
Were the champagnes fairly presented? Participants in the present study only had limited access to cues such as the size of the bubbles, the quality of the mousse, and the amount of dissolved CO2 since they were sampling in random order sequentially. For example, the size of the bubbles can be used to distinguish between Champagne and Cava. These cues provide quality information which could have been used by the tasters to distinguish between the wines they were sampling [18–20], but there is little evidence to suggest that they would provide information about the proportion of white versus red grapes in the wine. Colour, on the other hand, could have provided an important cue. This study therefore employed blind tasting.
Although blind tasting is a technique that is commonly used, it may not provide results that are transferrable to normal, namely sighted, taste perception. Pangborn and her colleagues  revealed that experts rated a rosé-coloured white wine as being sweeter than the untainted (uncoloured) white wine. By contrast, the non-experts’ sweetness ratings were not influenced by the colour of the wine. As such, experts who, knowingly or unknowingly, use colour when assessing the proportion of white and red grapes in a sparkling wine might be misled [22–24]. It is also worth noting that the glass itself may also have had an influence on the flavour .