Reduction or conversion of the wine contained acids through various cellar technical measures. This is necessary especially in bad years when the grapes have reached an insufficient degree of ripeness. Under EU law, this is basically fresh grapes. grape, partially fermented grape must, young wine and wine. However, this is dependent on the growing zone,
For the wine-growing zone A ( Germany, except Baden region) and Weinbauzone B (German cultivation area to bathe and Austria ) partial deacidification is permitted (but not one leavening ). A high acidity in grape must with low PH value indeed causes a more pure fermentation, but is probably from 12 g / l appropriate. Grape musts are usually deacidified to about 9 to 10 g / l.
Deacidification can also be carried out with grape must, which results in lower flavoring than in wine. By the stay of potassium in later wine results in a "rounder" acidity with a full, harmonious impression. Another advantage is that this may result in an eventual later malolactic fermentation is favored. Possible disadvantages are the risk of off-flavors and a change in the color of red wine. In Austria quality wine is at least 4 g / l tartaric acid (Total acid) prescribed. There are several methods, but for the application of tartaric acid content is crucial:
The process, usually referred to as malolactic fermentation, is not deacidification in the narrower sense of the word, but should also be mentioned. It is (mostly in red wines) after alcoholic fermentation, the harsher malic acid in the milder lactic acid converted. See under malolactic fermentation,
This is done by adding pure, carbonate of lime (calcium carbonate) or potassium bicarbonate (Potassium hydrogen carbonate). These substances form with the tartaric acid a sparingly soluble salt, which precipitates in the form of calcium tartrate. The malic acid but it is not diminished. See also below Contact method,
The method called double salt deacidification occurs when too high levels of these two acids are present in the wine to the largest extent. In this case, carbonate of lime is not enough. It is a portion of the wine, a special acidification lime (calcium carbonate with the addition of double salt crystals) is added, which precipitates both acids in the form of a double salt. After that they have to filtration be removed and make a return with the remaining amount.
This process is similar to double salt deacidification, but not only double salt but also tartaric acid is added. This results in a particularly intense deacidification of tartaric acid and malic acid and it can be set any desired acidity. In Germany, this is known by the term "Malitex method".
Here, an acid-rich is blended with a low-acid wine and set the desired acidity. There are corresponding procedures or formulas, see below waste cross,
Complete listings of the numerous vinification measures and cellar techniques, as well as the wine-regulated wine, sparkling wine and distillate types are under the keyword winemaking contain. Comprehensive information on wine law is available under the keyword wine law,