In Search of Lost Flavors

Legal uncertainties

However, despite the rapid growth, fundamental legal questions remain open, explains Prof. Harald Scheiblhofer, head of the cellar management department at the wine school and the Federal Office for Viticulture in Klosterneuburg (Austria). There is still no definition from the OIV regarding what exactly de-alcoholized wine actually is. Furthermore, it is not precisely defined internationally which technologies may be used and which substances may be added. Therefore, individual national regulations, such as those in Austria and Germany, contradict the currently applicable EU wine law. "The question is: Does practice adapt to the law, or is it the other way around? Currently, the trend is more towards adapting the law," explains Scheiblhofer.

To remove alcohol from wine, engineers and developers are currently working with three very different technologies: reverse osmosis, membrane processes, and vacuum distillation.

In reverse osmosis (nanofiltration), the wine is pressed through a semipermeable membrane. Water, ethanol, and volatile acids are removed, thus concentrating the wine. This technique is well-suited for reducing alcohol by one to two percent, but not for complete de-alcoholization. For every degree of alcohol that needs to be removed, the wine is pressed through the membrane once, and the varietal aromas of the wine cannot be separated. The volume loss must be compensated by adding water. However, this is not allowed in the EU. As Harald Scheiblhofer explains, the systems are inexpensive to acquire because the process functions technically simply. Improved devices are currently being developed that would also allow for complete de-alcoholization. "In terms of aroma preservation and energy consumption, they could be far superior to existing systems in the future," he predicts.

In the membrane process, wine circulates at room temperature and atmospheric pressure through a membrane that allows gaseous ethanol, i.e., alcohol, to diffuse through its pores. According to Harald Scheiblhofer, membrane processes offer many advantages, especially in terms of taste, but also in energy consumption. This technique also allows for the production of small systems, and it is possible to combine it with vacuum distillation. For corrections of up to 20 percent alcohol removal, membrane processes are very efficient. However, for the production of alcohol-free wines, the efficiency decreases significantly. Current systems can de-alcoholize about 1,000 liters per day. Vacuum distillation achieves about the same amount in one hour.

For complete de-alcoholization, vacuum distillation is particularly suitable, for which there are various technologies: low-temperature processes, high-temperature processes, and spinning cone columns. With modern systems, alcohol is distilled at a temperature of 30°C. However, a large part of the aromas is also removed, as they evaporate faster than alcohol.

The combination of different processes is particularly promising according to Scheiblhofer - but this is not always legal.

The key to success: the aromas

The complete removal of alcohol is technically not a problem. However, the difficult part is recovering the aromas that are lost in the process. Irem Eren from BevZero explains: "No current technology can fully capture the aromas. We can separate them in a single fraction, but part of it is lost in the process. Moreover, these aromas contain ethanol, which means they cannot be reused in a zero-percent product."

This is also confirmed by Claudia Geyer, co-founder of Flavologic and aroma recovery specialist: "The existing de-alcoholization processes are unable to replicate the original flavor profiles. They use additives that compromise quality. The removal of alcohol often leads to the loss of aromatic compounds and affects the authentic flavor quality of the end product."

However, intensive research is being conducted on new solutions and improvements. Flavologic is working with so-called adsorber resins to capture the aromas.

BevZero, on the other hand, has developed a new technology called ClearAlc in partnership with the Spanish company TOMSA Destil. This allows for the separation of aromas into different fractions, of which only certain parts can be reused. "We can reduce the yield loss from 30 percent to twelve to 15 percent, which leads to less sugar being added to de-alcoholized wines," reports Irem Eren.

Another approach is being pursued by the Austrian start-up VinTech. Their technology uses the gases produced during fermentation. These contain many aromas that were originally present in the wine. VinTech captures the fermentation gases and reintroduces them as re-aromatization to the de-alcoholized wine, explains co-founder Hannah Erdmann. It is advisable for the winemaker to collaborate with VinTech from the very beginning. "This is the ideal case: We have a wine and its aromatic fermentation gases." The major technical challenge is to introduce the aroma-rich gas into the liquid in such a way that it does not immediately escape but also does not create sparkling wine. The process is still in the testing phase.

The costs of the processes are still high

Producing alcohol-free wines with these technologies is still very expensive for winemakers. Prof. Harald Scheiblhofer is well aware of the cost ranges. They all fall within the five to seven-figure range:

A system for reverse osmosis plus hydrophobic membrane starts at around 250,000 euros, while the process plus vacuum distillation costs about 500,000 euros, double the amount.

It becomes even more expensive with vacuum distillation or a spinning cone column: Wineries must invest about one million euros or more.

A system based on reverse osmosis and the addition of water costs around 100,000 euros, while small systems are available from about 50,000 euros. They are not allowed for wine in many countries. However, this technology is permitted for "wine-alternative beverages" as well as beer.

If additional aroma recovery is purchased as a service from Flavologic, it costs up to one euro per bottle. In addition to the pure system costs, expenses for buildings, customs warehouses - as pure alcohol is produced - and explosion protection must be considered. According to Prof. Scheiblhofer's calculations, these additional costs can quickly add up to one million euros. Therefore, large systems for contract production are hardly calculable with an investment sum of less than two million euros.

Whether de-alcoholized wines will win the favor of consumers, or whether alternatives based on tea ("sparkling teas"), verjus, or kombucha will prevail, is still unclear. However, investments are associated with risks for wineries in any case. The example of de-alcoholized beers and their increasing market shares shows that perseverance could pay off in the future.