Definition: De-alcoholisation of wine

The terms "uncollated" and "unfiltered" are now often associated with high-quality wines. It is assumed that these wines are produced using the most natural traditional methods and are therefore superior. However, careful fining and filtration have produced and continue to produce many great wines. This has led to a trend towards wines produced with minimal intervention, to the extent that winemakers who use this new dealcoholisation process prefer to talk about it as little as possible.

Treatment using a spinning cone column has nothing in common with fining or filtration. Large estates such as Beringer, Geyser-Peak, Kendall-Jackson, Meridian and Mondavi are among more than a hundred that have tested this new technology. In the United States, the ability to reduce the alcohol content in wine leads to substantial savings for one simple reason: a government tax is levied on the alcohol contained in wine.

The weather conditions during the long sunny season when the grapes ripen produce fully mature bunches containing a lot of sugar. This results in wines that are very rich, often heavy and alcoholic. The alcohol content often exceeds 14%, which means a higher tax is levied by the government. In the past, to avoid this, some wines were diluted with water. The result was not always positive, and was even illegal in some states. This explains the invention of a new sophisticated tool designed to lower the alcohol content.

The spinning cone column was originally developed in New York and then perfected by Australian winemakers. Wine that passes through this complicated, electronically controlled machine is separated from both its alcohol and its aromas. In a second stage, the alcohol is removed, while the other essences containing the aromatic extract are reincorporated into the liquid. It should be noted that a wine stripped of almost all its alcohol has nothing left to enhance the aromatic extract. At the same time, it loses all its body. The liquid coming out of the machine is truly undrinkable. For this very reason, most attempts to produce alcohol-free wines have failed.

On the other hand, the dealcoholisation technique remains of interest when the aim is to reduce the alcohol content rather than eliminate it completely. This partial dealcoholisation is achieved by treating only a limited volume (approximately 10%) of a full vat. For example, from a 20,000-litre vat, 2,000 litres are removed for dealcoholisation. This virtually alcohol-free fraction is then blended back into the 18,000 litres of the original vat. In the presence of alcohol, the treated portion regains its initial aromatic level. However, the alcohol percentage of the entire vat has decreased.

During comparative tastings of the same wine before and after dealcoholisation, the transformation is noticeable. It becomes more difficult to determine exactly whether this results in a loss or gain in quality. For example, a full-bodied Chardonnay, vinified in oak barrels, with an alcohol content of 14.5%, was well received, with a certain heaviness before treatment. Reduced to 13.5% alcohol, the same wine lost some of its opulence but gained in finesse and liveliness. Another Pinot Noir with 15% alcohol had rich flavours of prunes, liquorice and aromatic herbs. Reduced to 13.5% alcohol, the same wine became at least as pleasant, with greater delicacy and aromas of cherry stone, menthol and aromatic herbs. Both variants were equally interesting. The only wine that showed a noticeable improvement was a heavy, thick Zinfandel with curious aromas. In its dealcoholised version, the fresh fruit flavours were brought to the fore.

Apart from the findings in terms of quality, the financial benefits outweigh any doubts that may remain. For Californian wineries, on wines with less than 14% alcohol, the tax reduction is around CHF 0.24 per litre. Over hundreds of thousands of litres, the sum becomes quite substantial. An estimated 4.6 million cases (41.4 million litres) of Californian wine have recently been processed using this technology.

Initially, dealcoholisation was introduced for the sole purpose of avoiding taxes. But now, for many oenologists, producing better-balanced wines has become the priority. The introduction of dealcoholisation makes it possible to harvest fully ripe grapes and produce wine from warm regions using the best raw materials. The processing costs amount to around 50 centimes (CHF) per litre. Given that only 10% of the total volume is dealcoholised, the impact on the cost price of the final product is negligible.

Obviously, this technology is only relevant to vineyards around the world where the climate allows for high ripeness of the harvest. California, Australia, South Africa, Chile, Argentina, several countries in southern Europe and northern Africa are candidates.