Prototype development for the recovery of wine aromas from fermentation gases

Abstract

Dealcoholised beverages are trendy. But this market segment is slowed down by flavour losses during dealcoholisation and by the reduced perception of flavours in the absence of alcohol.

Adding foreign flavours distorts the product. One alternative is to add wine aromas that are already lost during alcoholic fermentation through evaporation. They represent a raw material with no additional costs and which is available in abundance. The recovery of volatile wine aromas from the fermentation gases is difficult because tiny amounts of the substance are present in a very large excess of carbon dioxide. Simply cooling the fermentation gases is not enough. In addition, the predominantly lipophilic aromas must be absorbed in a lipophilic, food-grade liquid. This is achieved by ‘gas scrubbing’ with cold ethanol. The process has been protected by a German [1] and a European [2] patent since 2022. In 2023, the process was published [3] and presented orally at the OIV congress.

In 2024, a first prototype was developed with modest means, which was designed for a must volume of 100 litres. The volatile aromas were captured at approx. -25°C in 100-200 ml of ethanol (96%), which was circulated. A Vigreux column with a mirrored vacuum jacket was used. The alcoholic concentrates obtained show aroma profiles typical of the grape variety, with particularly intense sweet primary aromas. The residual gas escaping from the apparatus is almost odourless. Wine aromas can only be smelled if the flow rate is too high (over 1 l/min). Towards the end of the fermentation, some acetaldehyde can also be detected.

The separation of the aromas from the ethanol used is crucial for the application in dealcoholised wines. A new technique, which is eligible for another patent, was used for this.

In addition to the improvement of dealcoholized wines, other applications are also being considered, such as fortified wines and distilling mashes. If a normal wine is fermented at a reduced pressure, large quantities of aromas and alcohol evaporate. The aromas are recovered using the technology presented, while the alcohol is removed. This is an elegant way to reduce excessive alcohol content. In any case, a valuable additional product is obtained: food-grade carbon dioxide that can be used in the beverage industry.

The process is being developed to market maturity as part of a Franco-German project under the brand ‘Montclair Tech’. It is supported by Bernard Magrez Start-Up Win (Strasbourg) and Triathlon, the entrepreneurship ecosystem of Saarland University.

References

[1] Neisius, J. (2022) Gärgaskondensation (DE 10 2020 105 765 B4). Deutsches Marken- und Patentamt. https://register.dpma.de/DPMAregister/pat/register?AKZ=1020201057652

[2] Neisius, J. (2022) GÄRGASKONDENSATION – FERMENTATION GAS CONDENSATION – CONDENSATION DES GAZ DE FERMENTATION (EP 3 875 569 B1) Europäisches Patentamt. https://register.epo.org/application?number=EP21156468

[3] Neisius, J. Revista Enólogos (2023), 143, 70-75.