Recent health trends have contributed to the increase in the interest in and demand for low- and no-alcohol beverages. Historically, the stigma of low- and no-alcohol beverages hasn’t been the most positive, though with health-conscious movements driving much of this demand, reversing this stigma will become paramount to brand success. Though the sample size is insanely small and thus not at all scientific, my own personal experience with no-alcohol wines has been rather disappointing. So far, I’ve yet to taste a no-alcohol wine that remotely comes close to tasting like the “full strength” versions, which is not surprising considering the fact that the alcohol itself plays a major role in the aromatic and flavor profiles of a wine.
Though the mechanisms themselves are not fully understood, alcohol (specifically, ethanol) imparts a “burning” or “warming” sensation in the mouth for many, while also influencing the overall perception of various aromas and flavors in a wine. As ethanol levels increase, sensory studies have shown decreases in fruity and floral aromas/flavors, and increases in wood and pepper aromas/flavors.
How one perceives the aromas/flavors of the wine in the mouth via retronasal mechanisms is complicated, but to grossly simplify, there is an initial aroma release when the sip is first taken, followed by another aroma release after the wine has been swallowed. So far, most peer-reviewed studies on retronasal aroma release have been using model wines, which are far less complex than “real” wines, which could impact factors related to aromas/flavor perception.
A study published September 2019 in the journal Molecules, aimed to improve upon the understanding of retronasal aroma perception by using actual wine instead of a simplified model wine. Specifically, they wanted to examine the effect of ethanol on aroma release in said real wine.
Brief Methods
The wine used for this study was a dealcoholized Tempranillo rosé wine from Spain (0.5%abv).
Ethanol was added to this wine to create two more ABV levels – 5% abv, and 10% abv – for a total of 3 ethanol level treatments.
To increase the aroma profile of the wines, 6 food-grade esters that are associated with fruity notes in wines were added to each wine. Esters were added immediately prior to the tasting sessions, to reach a final concentration of 4mg/L. Analysis determined the 6 esters added were present in the wine prior to the start of the experiment in negligible amounts, if at all.
10 people participated in this study – 4 men, 6 women, between 18 and 36 years old.
To study how aromas are perceived in the mouth during and after tasting, the following procedure was employed:
- Each subject took 15mL of wine into their mouths, held it for 30 seconds, and then spit it out.
- 30 seconds after spitting out the wine, a DVB/CAR/PDMS-coated SPME fiber with a homemade adapter was inserted into the mouth of each subject.
- After 2 minutes (where no swallowing was allowed), the fiber was removed and immediately analyzed in a gas chromatograph (GC/MS). (This was the “immediate oral release” measurement).
- 4 minutes after spitting out the wine, a second fiber was inserted into each subject’s mouth and again left for two minutes and finally analyzed by GC/MS. (This was the “prolonged oral aroma release” measurement).
Analyses were performed for each wine (0.5%, 5%, and 10% abv) three times.
Selected Results
- The effect of subject on aroma release was significant for all compound studied.
- This means that individual people perceive aromatic compounds differently in wine, depending upon individual physiological characteristics, and so forth.
- The effect of ethanol content was less important in influencing aroma release than individual subject characteristics were.
- Isoamyl acetate and ethyl hexanoate were not impacted by ethanol content to a significant degree.
- Ethyl butyrate and ethyl pentanoate showed significantly greater immediate oral release after rinsing with the higher ethanol wines compared with the 0.5% wines.
- Ethyl octanoate and ethyl decanoate showed significantly less immediate oral release after rinsing with the higher ethanol wines compared with the 0.5% wines.
- The variability in the behavior of each of the 6 esters could be related to structural or other physiochemical differences, though more studies would need to be done to determine the exact mechanisms.
- The interaction between subject and ethanol content was significant for all compounds studied.
- This means that the effect of ethanol concentration on oral aroma release was dependent upon individual subjects — meaning that ethanol concentration will affect aroma release for each person differently, depending upon who they are the what their physiology is.
- Results were very similar for the prolonged aroma release measurements.
- Aroma release for 5 out of the 6 esters were significantly affected by ethanol concentration. The 6th ester, ethyl hexanoate, showed an increase with increasing ethanol concentrations, though this value was not significant.
Conclusions
Overall, the results of this study showed a couple of things. First, that ethanol content influences the release of aromas retronasally when tasting/drinking wine. Second, and more importantly, individual variation affects retronasal release of aromas even more than ethanol content.
While the sample size was very small – only 10 subjects (I’d love to see a much larger study), so results should be taken with a grain of salt – the results highlight the fact that how we taste wine is not universal. Everyone tastes something different, or at least in different ways. In this study, individual variation had the most influence on aroma release after tasting wine. Additionally, individual variation coupled with ethanol concentration changes added even more complexity. Specifically, while in general aroma release of many of the study esters changed with increasing ethanol concentrations, exactly how that aroma release changed depended on two factors: what the structure/physiochemistry of the ester compound was and who was drinking the wine to begin with.
What does this all mean for producers of low- and no-alcohol wines? Well, unfortunately this study doesn’t really give you a recipe for how to make your wines so that they taste the same as “full strength” alcohol wines. Basically, what this study implies is that aroma release of fruit-associated esters changes with alcohol content, and figuring out how to elicit that same release without the alcohol is going to be the next step in low- no-alcohol wine research (at least in the area of aromatics).
This study also implies that even though some people may observe certain changes to a wine’s aroma when presented with different alcohol levels, other people may observe something completely different.
Overall, this study suggests that aroma release changes with changing alcohol levels in wine, but how that change is perceived depends upon who is drinking it.
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