Alcoholic strength Counting in percentages It has been proven that alcohol in moderate doses has beneficial effects on health. The alcohol in wine is ethyl alcohol, the result of the transformation of sugars due to the action of yeasts in the grapes. It follows that a grape with a higher sugar content will give a higher level of alcohol. This is measured in millilitres at 20°C and may be defined as the alcohol percentage by volume. To give a practical example, when a wine is labelled as 11° this means that it contains 11% alcohol by volume (or 110 millilitres of alcohol per litre of wine), one of 12° contains 12% of alcohol and so on. By law table wines have to contain at least 8% (or 9° of alcohol). In certain cases the label may state 'potential degree of alcohol'; these are usually sweet wines which still contain sugars which, at least in theory, could ferment and make more alcohol; this is the potential degree of alcohol. Alcohol is one of the elements which has the biggest effect on the quality of wine. It is the main factor responsible for the smoothness, mellowness and roundness and it contrasts with and masks the effects of acidity and astringency, acts as a support for the primary aromas and plays a key role in the various process the wine undergoes during development. This is why it is very important to have a reasonable level of alcohol even if it has to be corrected during alcoholic fermentation. Italian law allows the alcoholic level to be corrected by a maximum of two units. This practice is not common among the more careful winemakers who pay the greatest possible attention to raising the sugar level in the grapes on the vine and not intervening later. In Italy the most common system is addition of concentrated rectified must, a colourless, odourless sugary solution obtained by removing the water from grape must - a sugar concentrate in practice. In France, and also in other countries, sugaring is allowed; the practice of adding sugar to feed the yeasts which will make it into more alcohol. In Italy the sugar level can only be increased, under strict controls, in fortified or strong sweet wines and in aromatized wines.