I’m sure you know that the amount of alcohol in different alcoholic drinks is expressed in degrees and it is possible that you know, at least approximately, the alcohol by volume or abv of the most popular drinks.
But perhaps you don’t know what it means exactly to have one level of alcohol by volume or another. It is very simple: the abv refers to the percentage of ethanol that the drink contains in relation to its total volume, measured at a temperature of 20 degrees centigrade.
The alcohol by volume is expressed, generally, as a percentage of the volume (% vol.). In the case of wine, if you want to know this information, you find it on the label of the bottle, as it is obligatory to show it. Therefore, for example, you can find the information on the label showing that a wine has 14% vol., which means that a litre of this wine contains 140ml of alcohol. Simple, right?
In the case of fermented drinks, like wine, beer, cider, the abv is generally between 3.5 and 15% vol. If we are talking about fortified drinks and spirits (gin, rum, brandy…) the abv increases to an average of between 15 and 40% vol.
Therefore, how much alcohol is there in wine?
According to current legislation, to be qualified as a wine, it must have an abv of a minimum of 9% vol. The councils of the various Designations of Origin may also establish certain minimum levels for the wines of their region: the Rioja D.O.Ca. demands that its red wines have a minimum abv of 11.5% and its white and rosés, 10.5% vol.
Generally speaking, a wine with less than 11% abv is considered to be low alcohol, medium if it has between 11% and 13% and high if it has more than 14% vol.
Factors that influence the alcohol by volume of a wine
You may ask what a wine’s alcohol by volume depends on. Well, fundamentally, it depends on the concentration of sugars in the raw material used for its production, that is to say, the grapes, as, as you already know, alcohol is obtained from the fermentation of these sugars.
And what does the level of sugar in grapes depend on? Well, principally, on the type of grape and above all, on its level of ripeness, which is, in turn, linked to the weather.
To a lesser extent, the abv of wine is also related to fermentation processes and subsequent post-fermentation treatments the wine is subjected to.
Climate change and the abv of wines
Perhaps you have heard that wine is getting more and more alcoholic: it’s true. The general trend over recent decades is for the alcohol content to increase and the principal reason behind it is the rise, in turn, of world temperatures. The vine uses hours of sunlight and warmth to generate sugar in its berries through photosynthesis, therefore, the greater the number of hours and the higher the degrees of temperature within the operational range, the more sugar it is able to synthesize. This will give sweeter grapes, and therefore, more alcoholic wines, even if the harvests take place earlier.
Abv and wine quality
One of the false myths around wine is that the alcoholic strength is related to quality. And it is untrue as a wine with more alcohol is not, necessarily, a better wine than one with a lower abv.
The source of this confusion is likely to be based on the fact that Reserva or Gran Reserva wines usually have higher abvs that table wines, but this does not automatically mean that any wine with a higher alcoholic content is a good one. Bear that in mind!
In fact, as you well know, a good wine is a balanced wine and high alcohol content can jeopardize this balance. Excessive alcohol content can also mask the aromatic richness.
Can a wine’s alcohol content be corrected?
Increasing a wine’s alcohol content through adding sugar other than that in the must (chaptalization) is prohibited in Spain although there are wine producing countries that allow it.
As for whether dealcoholisation is permitted, the answer is yes, although with certain reservations. The abv of a wine can be reduced during or after fermentation, although this alteration can affect the quality of the wine and should only be carried out by suitably qualified experts.
In fact, many current research studies are taking place into this subject. On one hand, they are looking for ways to reduce the increase in the abv of wine provoked by global warming, as we have already mentioned. On the other hand, they are also looking to meet the demand from some consumers who require wines with lower alcohol content (think of, for example, drivers.) Up until now, during fermentation, the alcohol content of wine could be reduced through a selective removal of sugars and experiments are being made into the use of different yeasts that could reduce the alcohol content producing less ethanol in the alcoholic fermentation without this loss leading to a reduction in quality.
Since 2010, the OIV (The International Organisation of Vine and Wine) has authorised the use of membranes to reduce the quantity of alcohol in wines, but always in compliance with the Code of Oenological Practices and in minimal quantities that do not lessen the quality of the product.
