The content of alcohol in wine refers to the proportion of ethanol; the main type of alcohol present. The theoretically achievable alcohol content of a wine can be calculated by the must weight already in the grapes. It results from the sugar (fructose and glucose) in the must, which is converted into alcohol and carbon dioxide during fermentation. In the 19th century, the French chemist Joseph Gay-Lussac (1778-1850) developed a system that represents the alcohol content in degrees (°), which is still partly used in Anglo-American countries. Today, however, it is internationally accepted and standardised within the EU that the alcohol content is given in percent by volume. The measurement is made at a temperature of 20 °Celsius.
There are four different terms for the alcohol content. Above all, there is interest in how much alcohol is actually contained in the drink. In most countries, the actual alcohol content is indicated on the label:
Actual alcoholic strength by volume: pure alcohol actually contained in must or wine.
Potential alcoholic strength by volume: Theoretical proportion which could be added by complete fermentation of the residual sugar. In Italy, this value is often expressed in terms of actual alcoholic strength by volume, for example "14% vol+4". In this specific case, this means a residual sugar equivalent to 4% alcohol, i.e. about 65 g (1% alcohol corresponds to 16 to 17 g sugar).
Total alcoholic strength: sum of actual and potential alcoholic strength.
Natural alcoholic strength by volume: total alcoholic strength before any enrichment.
During fermentation, 10 grams of sugar per 1,000 grams of must yield 0.66% vol alcohol. A content of 8 grams of alcohol per litre corresponds to about 1° or 1% vol. The conversion formula is % vol x 7.894 = grams of alcohol per litre (g/l) of wine. At 12% vol this gives 94.7 g/l. In a bottle of wine with 0.75 litres this is 71 g of pure alcohol. One eighth of wine contains about the same amount of grams of alcohol as it contains by volume. This means that one eighth of wine with 12% vol. contains 12 g alcohol. A simple method for determining the alcohol content is the Rebelein method.
So what is the alcohol level when you drink a bottle of 0.75 litres of wine alone (that is three quarters or six eighths of wine) with an alcohol content of 12% vol? It should be noted that this also depends on physical condition, drinking speed, gender and other factors. Calculated over the thumb, these "three quarters of wine" result in a man weighing around 85 kg and drinking for two hours in a gross amount of 1.2 per thousand (see formula under blood alcohol concentration). With regard to the acceptable amount to be consumed, see under Health.
The indicated alcohol strengths are to be understood as approximate guide values. For all alcoholic beverages there are partly different legal requirements in the countries regarding minimum and often also maximum values (see under the respective keywords such as cognac and at the countries):
|non-alcoholic beer||0.0 to 0.5|
|Light beer||2,0 to 3,2|
|Beer (top-fermented beer, Altbier, Kölsch)||4.5 to 5.4|
|Strong beer (bock beer)||5 to 12|
|Wine - light||to 11|
|Wine - medium heavy||to 13|
|Wine - heavy||over 13|
|Sparkling wine - cava, sparkling wine, champagne, etc.||9 to 13|
|fortified wines - Malaga, Port, Sherry etc||15 to 19|
|Brandy - Armagnac, Cognac, Lourinhã, Metaxa etc.||36 to 45|
|Liqueur||11 to 55|
|Rum||38 to 80|
The "right" alcohol content has a positive influence on the taste. Many flavourings are soluble in alcohol. Wines that are too heavy on alcohol lose their balance and can have an alcoholic or gangrenous effect. They appear less fragrant because the aromas are bound to the alcohol. In addition, the varietal typicity suffers from this. On the other hand, alcohol conceals acids. A dry aged wine with low residual sugar and high alcohol content can taste relatively sweet.
Wines with high alcohol content have more body (fullness), less alcohol underlines the elegance. Wines with (too) low alcohol content often taste characterless and hollow (empty). At the degree also known as "sweet spot", the wine achieves the most perfect harmony between aroma, fruitiness and taste. For (too) high alcohol wines, this harmony can be achieved by the process of alcohol reduction.
According to the EU regulation, the actual alcohol content on the label must be indicated in volume percentages by full or half units, rounded if necessary. The declared value may deviate from the content determined by analysis by a maximum of 0.5% vol. In the case of wines with indication of the year of harvest, wines aged in bottles for more than three years, sparkling wines, semi-sparkling wines, liqueur wines and wines from overripe grapes, the declared alcoholic strength by volume may differ from that determined by analysis by a maximum of 0.8% vol. The symbol "% vol" shall be added to the value; this figure may be preceded by the terms "actual alcoholic strength by volume" or "actual alcohol" or the abbreviation "alc.
Furthermore, there are specifications for minimum alcohol content per wine-growing zone. For A and B these are as follows since 2009: For wine (formerly table wine) at least 6.5% (corresponds to 11.2 KMW, which may be harvested) plus a maximum possible enrichment of 2% results in 8.5% for the finished wine. For all other wine-growing zones at least 9% applies. However, the requirements for country wine, quality wine and Prädikatswein may be regulated by the countries themselves and therefore vary greatly (also per wine growing region). The respective regulations are included in the country keywords.
Subject to country-specific regulations, enrichment with certain sugar-containing agents may also be carried out to increase the natural alcohol content. The addition of alcohol to the finished, i.e. already fermented wine is called spriting. The alcohol content can be determined by various methods; see analytical testing. A tabular list of all wine ingredients is included under the keyword total extract (.
All aids, work and measures in the vineyard during the vegetation cycle can be found under vineyard care. Complete lists of the numerous cellar techniques, as well as the types of wine, sparkling wine and distillate regulated by wine law can be found under vinification. Comprehensive information on wine law can be found under wine law.