The importance of alcohol in wine
Alcohol (or ethanol) is probably the main reason why we drink wine today. Not only for the pleasure it provokes since ancient times but simply because grape juice is transformed through alcoholic fermentation into wine. It is the yeast that transforms the sugar in the grape into ethanol (EtOH).

When I first got to know the
DOQ Priorat in Spain I couldn’t believe why anyone would complicate the viticulture by planting vines on slate (llicorella) stone slopes where people have to crawl up the mountain to take care of the vineyards. Archaeologists discovered a Roman settlement in the region where rests of amphorae were found. A more then plausible explanation for the Romans to cultivate wine in such hard circumstances (extremely dry, stone soil and very low production) is the high content of alcohol Priorat wines have (it can easily go to 18-19% abv). Alcohol provides microbial stability. The lower the alcohol level the more hostile the environment. This may explain why the Romans were keen on high alcohol levels in wine to be transported in open amphorae during their long voyages in the extended Roman Empire.

Alcohol is an organic solvent that is capable of extracting colour and phenolics from the contact with skins of red grapes during fermentation. Also during maceration alcohol extracts colour and flavours from the wine in contact with the ‘must’. In the case of barrel ageing, alcohol extracts oak flavours.
Besides the alcoholic transformation of sugars, alcohol also binds with grape acids to produce fruit esthers, a by-product of alcohol that affects the aroma of a wine. This is particularly common in white wines fermented in a cool reductive way.

Alcohol provides structure, texture and flavours to wine and contributes hugely to the mouth feel and body.
In taste alcohol contributes a sweet sensation to wine. It can also be perceived as bitter, especially in a white wine with little flavour and high alcohol content. In the mouth it has a warm or even hot feeling according to the percentage of alcohol by volume.
The texture of a wine is influenced a lot by alcohol that has a somewhat viscous texture and contributes greatly to a wine's body or thickness. As a result, wines with high alcohol content will generally feel fuller bodied than those with low alcohol.
The structure of wine is build up by alcohol and flavours. Grapes are around 80% water and 20% sugar; once the sugar is fermented you end up with water, alcohol and flavourings. Alcohol is determined in building up the structure and holding together the balance of a wine.
Alcohol, as well as tannins, also allows the wine to age and is thus important for wines that improve with bottle ageing.

As shown in the latest medical studies, alcohol in wine can provide health benefits in moderate consumption. It may help lower cholesterol and protect against heart disease. Of course excess alcohol consumption can lead to many diseases. Government health warnings are mentioned on the label in the US and will become a legal requirement in many other countries too.
Wine as an alcoholic beverage is regulated and has legal implications in most countries. Alcohol levels provide also a method of classifying and taxing wines. Each country has it’s own excise tax in addition to the Value Added Tax which provide significant financial contribution to a country.

Today daily wine consumption is gaining generally and wine is no longer seen only as a luxury product. Wine has been consumed mainly on festive occasions or paired with food. Modern life has become stressful and the joy of a glass at home after work or on a terrace of a bar with friends is getting more popular. As drinking wine is in a democratisation process the discussion on the raise of alcohol levels is a hot topic and retailers are demanding lower alcohol content to respond to a new market trend. Alcohol, being a drug, has a negative connotation in society and public drunkenness is seen as vulgar. But are high alcohol levels in wine a problem for the consumer? People like to drink wine on a regular base and therefore look for a ‘light’ wine, they keep the strong, heavy wines for the weekend.

Of course religion and cultural background play an enormous role in the perception of alcohol beverages in society. Muslims forbid alcohol. For Christians alcohol is not only allowed, but also exists as a religious symbol, and Norse Paganism is probably the most enthusiastic drinking religion of all.

There are a number of explanations for elevated alcohol levels in wine but two seem to be generally accepted: the global warming and the more ‘international’ sweet style of wine. Average temperatures have risen noticeably and warmer growing seasons usually result in riper grapes with higher sugar levels. Grapes are also being picked in a later stage in order to develop more phenolics and accordingly sugars to produce wines with a sweeter fruit profile.
To obtain lower alcohol levels the technique is to remove alcohol from wine after fermentation with the use of new technologies like reverse osmosis, where alcohol is taken out by distillation.

For me, the alcohol level of a wine doesn’t matter as far as the wine is well equilibrated. Noticing the alcohol is disturbing but great wines with high alcohol levels are being made. In fact in a quality wine you shouldn’t notice too much any of the components of a wine, in stead the result should be a new harmonic taste, structured and well balanced with personality provided by ‘terroir’, the natural aspects a grape contains and the wine maker’s skills.

Wine is ultimately for the pleasure and joy of life, and it’s obvious that the role in society of wine would be quite less significant if it didn’t contain alcohol.

August 2009, Stefan Lismond.