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Wine dealcoholization - how alcohol is removed

Not long ago alcohol-free wine was a byword for bland, sweet juice, but that is changing. More and more wines with reduced alcohol really do resemble wine, and behind it stands serious technology. The key point is that these wines are not made so that alcohol never forms, but the opposite: a normal wine is made first, and then the alcohol is removed from it. It is a hard task, because alcohol carries flavour, body and structure, so removing it easily leaves a hole. The two main methods are reverse osmosis and the spinning cone column, both approved by regulation. Here is how exactly they work, what they lose, what they manage to keep and why good alcohol-free wine is still a technological challenge, not mere dilution.

First the wine, then removing the alcohol

The most important thing to understand is that dealcoholization is removing alcohol from finished wine, not making it alcohol-free from scratch. First the grapes ferment normally, giving a fully fledged wine with all its aroma, acidity and structure. Only then, on the finished product, are technical methods applied to take out the alcohol. This approach differs from grape juice, which was never wine. As a result, alcohol-free wine retains at least part of the character of real wine, rather than being just sweet must. Understanding this order is the key to the whole topic. The whole art lies in taking out the alcohol while keeping as much as possible of what makes wine wine. It is far harder than it seems.

Why removing alcohol is hard

Removing alcohol from wine is not the same as pouring out water, because alcohol plays many roles in wine. It carries part of the aroma, because many volatile scent compounds are bound up with it. It also gives body, smoothness and a sense of fullness in the mouth, and balances acidity and sweetness. When it is removed, the wine easily becomes thin, acidic and aromatically impoverished, with a perceptible hole where the alcohol was. That is why the real challenge is not taking out the ethanol itself, but doing it without destroying the rest. Good methods try to protect the aromas and the balance, and the best ones even recover volatile compounds and return them to the wine. This shows that dealcoholization is a delicate operation, not brutal evaporation. At stake is whether the result resembles wine at all.

Reverse osmosis

The first main method is reverse osmosis, based on membranes. The wine is passed under high pressure through a semipermeable membrane with microscopic pores. The membrane lets small molecules through, like alcohol and water, and holds back the larger compounds responsible for flavour and aroma. In this way the water-alcohol fraction is separated from the rest of the wine. Alcohol is removed from that fraction, for example by distillation, and the remaining water is returned to the wine to restore its volume. The advantage of reverse osmosis is working at low temperature, which protects delicate aromas from heat. It is a precise method, allowing alcohol to be lowered gradually and in a controlled way. It is widely used both for a light correction of strength and for deep dealcoholization all the way to alcohol-free wine.

The spinning cone column

The second main method is the spinning cone column. It is a kind of gentle vacuum distillation at low temperature, run in a device with rotating cones that spread the wine in a thin layer. The process usually runs in two passes. In the first, at a very low temperature, the delicate, volatile aroma compounds are captured and set aside. In the second, at a slightly higher temperature, the alcohol is removed. At the end the previously captured aromas are returned to the dealcoholized wine. Thanks to the short contact time and low temperature, this method protects aromas well from thermal degradation. It is an advanced technique, valued precisely for its ability to recover and restore the scent that would otherwise easily be lost. The spinning cone is today one of the most refined tools of dealcoholization.

The two methods side by side

The two methods are easiest to compare in a table. The one below shows their essence, how they work and their strength. It is a simplification, because details depend on the device and the aim, but it captures the differences well.

The table shows the common denominator of both methods: working at low temperature to protect aromas, and separating alcohol from the rest of the wine. They differ mainly in mechanism, membrane versus gentle distillation, and in that the spinning cone emphasises scent recovery.

What is lost and what is kept

No method is perfect, and something is always lost. Removing alcohol changes most of the wine’s chemical parameters, because ethanol helped create its balance. Most often body and fullness in the mouth suffer, because it was alcohol that gave smoothness and a sense of volume. Sometimes acidity becomes prominent, since the alcohol that balanced it is gone. Aromas can be largely saved, especially with methods that recover scent, but some volatile notes are lost anyway. That is why alcohol-free wines are often lightly sweetened or adjusted, to balance the loss of body. The best examples can surprise and really resemble wine, but they still differ from the original. Awareness of what is lost lets you fairly judge what to expect from such a wine.

The degree of alcohol reduction

Dealcoholization is not only zero alcohol, because it can be lowered to various degrees. Sometimes it is a light correction, for example shaving off one or two percent, when a wine from a warm vintage came out too alcoholic. It is a popular use that improves balance without radically changing the character. Another aim is producing low-alcohol wine, of much reduced strength. The most demanding is full dealcoholization to alcohol-free wine, because the deeper the removal, the greater the risk of losing character. So the scale of reduction decides the difficulty of the task and how much the wine must then be corrected. This shows that dealcoholization is a whole spectrum, not one operation. A light correction and full alcohol removal are entirely different challenges.

Legal status and acceptance

Both main methods are approved by regulation, which matters for the market. Both reverse osmosis and the spinning cone column are approved in the guidelines of the international wine organisation and in EU regulations. This means wines dealcoholized by these methods can be legally produced and sold. It is important, because it gives the category a framework and credibility. Growing interest in a healthier lifestyle and cutting back on alcohol means the market for alcohol-free and low-alcohol wines is growing fast. Producers invest in technology because they see real demand. A clear legal status lets these wines be treated as a full category, not a curiosity. This in turn drives further development and quality improvement.

Wine versus other alcohol-free drinks

It is worth seeing wine dealcoholization in a broader context. A similar challenge applies to alcohol-free beer, where alcohol must also be removed or fermentation limited without losing flavour. In beer, fermentation is often interrupted or similar membrane and distillation techniques are used. Wine is harder, though, because its flavour is more complex and more tightly intertwined with alcohol. Comparison with beer shows that this is a shared problem of the whole alcohol-free drinks category: how to remove the alcohol but keep the soul of the drink. You can read more about the analogous challenge in beer in the post on alcohol-free beer. This shows that dealcoholization is a broader phenomenon, and wine is one of its hardest cases.

What it means in the glass

For the drinker, dealcoholized wine is today a lottery, though increasingly a successful one. The best examples manage to keep a recognisable aroma and decent balance, though they are usually lighter in body than the original. Weaker ones can be thin, acidic or oversweetened, when the producer clumsily tried to patch the hole left by the alcohol. It is worth approaching them with openness but also realism, because it is still a different category from classic wine. A good clue is choosing producers who use methods with aroma recovery. If you want to deliberately compare how wine changes without alcohol, record your tastings in the app and note your impressions. Dealcoholization is a fascinating area in which technology chases flavour, and the difference between a successful and a failed wine can be huge.

The key points

Alcohol-free and low-alcohol wine is made by removing alcohol from finished wine, not by making it alcohol-free from scratch. It is hard, because alcohol carries aroma, body and balance, so taking it out easily leaves a hole. The two main methods are reverse osmosis, in which a membrane under pressure separates alcohol and water, and the spinning cone column, that is gentle vacuum distillation that captures and restores aromas. Both work at low temperature and are approved by regulation. Most often body and fullness are lost and acidity becomes prominent, though aromas can be largely saved. Alcohol can be lowered lightly or completely, and the deeper, the harder. The best alcohol-free wines really resemble wine, but they still differ from the original.