In search of the lost flavours

Legal uncertainties

However, despite the rapid growth, fundamental legal questions remain unanswered, explains Prof Harald Scheiblhofer, Head of the Cellar Management Department at the School of Viticulture and the Federal Office of Viticulture in Klosterneuburg (Austria). For example, there is still no definition from the OIV as to what exactly dealcoholised wine actually is. In addition, there is no precise international definition of which technologies may be used and which substances may be added. As a result, individual national regulations such as those in Austria and Germany contradict current EU wine law. "The question is: is practice adapting to the law or is it the other way round? At the moment, the trend is more in the direction of adapting the law," explains Scheiblhofer.

Engineers and developers are currently working with three very different technologies to remove the alcohol from the wine: Reverse osmosis, the membrane process and vacuum distillation.

In reverse osmosis (nanofiltration), the wine is pressed through a semi-permeable membrane. This removes water, ethanol and volatile acids, thereby concentrating the wine. This technique is well suited for reducing alcohol by one to two per cent, but not for complete dealcoholisation. This is because the wine is pressed through the membrane once for each degree of alcohol to be removed, and the typical varietal flavours of the wine cannot be separated. The loss in volume must be compensated for by adding water. But this is not permitted in the EU. As Harald Scheiblhofer explains, the systems are inexpensive to purchase because the process is technically simple. Improved devices are currently being developed that would also allow complete dealcoholisation. "In terms of flavour retention and energy consumption, they could be far superior to the existing systems in the future," he predicts.

In the membrane process, wine circulates at room temperature and atmospheric pressure through a membrane that allows the gaseous ethanol, i.e. the alcohol, to diffuse through its pores. According to Harald Scheiblhofer, membrane processes offer many advantages, especially in terms of flavour, but also in terms of energy consumption. This technology can also be used to produce small systems and can also be combined with vacuum distillation. Membrane processes are very efficient for corrections of up to 20 per cent alcohol removal. For the production of non-alcoholic wines, however, efficiency decreases significantly. Current plants can dealcoholise around 1,000 litres per day. Vacuum distillation can achieve about the same quantity in one hour.

Vacuum distillation, for which there are various technologies, is particularly suitable for complete dealcoholisation: Low-temperature processes, high-temperature processes and spinning cone columns ("spinning cone column"). The alcohol is distilled at a temperature of 30°C using modern plants. However, this also removes a large proportion of the flavours, as they evaporate faster than alcohol.

According to Scheiblhofer, the combination of different processes is particularly promising - but this is not always legal.

The key to success: the flavours

The complete removal of the alcohol is technically not a problem. What is difficult, however, is recovering the flavours that are lost in the process. Irem Eren from BevZero explains: "No current technology can completely capture the flavours. We can separate them into a single fraction, but some are lost in the process. In addition, these flavours contain ethanol, which means that they cannot be reused in a zero-percent product."

This is also confirmed by Claudia Geyer, co-founder of Flavologic and specialist in flavour recovery: "The existing dealcoholisation processes are not able to recreate the original flavour profiles. They use additives that impair the quality. Alcohol removal often leads to the loss of aromatic compounds and impairs the authentic flavour quality of the end product."

However, intensive research is being carried out into new solutions and improvements. Flavologic, for example, works with so-called adsorber resins to capture the flavours.

BevZero, on the other hand, has developed a new technology called "ClearAlk". This allows the flavours to be separated into different fractions, of which only certain parts are reused. "This allows us to reduce yield loss from 30 per cent to 15 per cent, resulting in less added sugar in dealcoholised wines," reports Irem Eren. BevZero uses its technology for Familia Torres' "Natureo", among others.

The Austrian start-up VinTech is working on another approach. Their technology utilises the gases produced during fermentation. They contain many of the flavours originally found in wine. VinTech captures the fermentation gases and returns them to the de-alcoholised wine as re-aromatisation, explains co-founder Hannah Erdmann. To achieve this, it makes sense for the winemaker to work with VinTech right from the start. "This is the ideal case: we have a wine and its aromatic fermentation gases." The major technical challenge is to introduce the flavour-rich gas into the liquid in such a way that it does not bubble out immediately, but also does not produce semi-sparkling wine. The process is currently still in the trial phase.

The costs of the processes are still high

Producing wines without alcohol using these technologies is currently still very expensive for winegrowers. Prof Harald Scheiblhofer knows the scale of the costs very well. They are all in the five to seven-figure range:

A system for reverse osmosis plus hydrophobic membrane is available from around 250,000 euros, the process plus vacuum distillation costs twice as much at around 500,000 euros.

It gets even more expensive with vacuum distillation or a spinning cone column: wineries have to invest around one million euros or more for this.

According to Scheiblhofer, a system based on reverse osmosis and the addition of water costs around 100,000 euros, while small systems are available from around 50,000 euros. They are not permitted for wine in many countries. However, this technology is permitted for "wine alternative drinks" and beer.

If additional flavour recovery is purchased as a service from Flavologic, for example, it costs up to one euro per bottle. In addition to the pure plant costs, the expenses for buildings, bonded warehouses - pure alcohol is extracted - and explosion protection must be added. According to Prof Scheiblhofer's calculations, these additional costs can quickly add up to a million euros. Large plants for contract production can therefore hardly be calculated with an investment of less than two million euros.

Whether dealcoholised wines will win the race for consumer favour, or alternatives based on tea ("sparkling teas"), verjus or kombucha, is not yet clear. However, investments are always associated with a risk for wineries. However, the example of dealcoholised beers and their increasing market share shows that perseverance in the future could pay off.