A reduction in alcohol in wine can be achieved using various physical and / or chemical processes. Especially in southern regions, this is a relatively common practice with the aim of aromatic and less alcohol-heavy wines. The simplest and cheapest form is the addition of fruit juice or grape juice, which is in the production of Cooler is applied, or by water (stretch). A certain one alcohol content can also be done by stopping the fermentation by means of cooling, which is practiced especially in Italy with simple wines. The result is sweet, tangy and low-alcohol wines. Thermal separation processes such as vacuum distillation (vacuum rectification) are mostly used.
The boiling point of pure ethanol is around 78 ° Celsius, which is the case with the distillation is exploited. However, this temperature would be too high for the purpose of alcohol reduction, since it would be valuable flavorings would be lost. Therefore, this is done at a reduced pressure of 0.07 to 0.15 bar (otherwise 1 bar) in the temperature range of 30 to 60 ° Celsius in order to keep material changes as low as possible. The dwell time and temperature should be as short as possible. Other procedures include electrodialysis High pressure extraction filtration (Nanofiltration, ultrafiltration), osmosis (Reverse osmosis, osmotic distillation), pervaporation and Spinning cone column, The requirements regarding the permitted procedures vary from country to country. In Austria, the relevant provision is that the "process is not explicitly specified, but suitable methods are vacuum distillation and reverse osmosis".
The basis for the production of non-alcoholic wine is not grape, but already fermented wine with a "normal" alcohol content between 9 and 14% vol. The alcohol must then be withdrawn from this in an additional step. It has gone through the same stages of development as normal wine and contains all of it even after alcohol reduction flavorings, For this reason, at best it retains the character of the original wine with an alcohol content of only 0.5% or less, which of course changes the taste somewhat.
A low-alcohol wine is either made like non-alcoholic wine or by blending de-alcoholised wine with normal wine. The alcohol content must be more than 0.5%, but may not exceed 5.0% vol. Both types of wine may be used to produce fermented sugar (i.e. residual sugar ) up to a maximum of 60 g / l grape must, RTK (rectified concentrated grape must) or sugar (Beet sugar) can be added. Likewise, the addition of carbonic acid and vegetable aromatics allowed.
On the label is this de-alcoholized, low-alcohol or by the instructions flavored to declare accordingly. More details about origin (only the land of the grape harvest is allowed), varieties and vintage are not allowed. A "dealcoholized wine" as well as non-alcoholic beer can be called "non-alcoholic" if the alcohol content is below 0.5% vol or 4 g / l. A complete dealcoholization is not mandatory despite the statement "non-alcoholic". The expression "without alcohol" may only be used on a food if the alcohol content is 0.0% vol. For technology reasons, this can never be the case for wines.
However, according to scientific studies, the residual alcohol content has no disadvantageous hazardous Effect on the organism, it corresponds approximately to that of various fruit juices and is even lower than the alcohol content of various foods such as kefir and even pastries. However, alcohol-free wines or beers with an alcohol content of up to 0.5% can also be dangerous for an alcohol addict. But that's not just a question of alcohol content, it's also a matter of mental health. There is no generally applicable limit from which it becomes "dangerous" (see under alcoholism ).
Within the EU, wines may have a maximum of 20% vol alcohol content be reduced. This can only be done using separation techniques such as distillation. Spinning cone column and osmosis or membrane techniques like pervaporation can be achieved. The procedure must not be used for wines, the other organoleptic Have defects. The removal of alcohol from wine must not be accompanied by a change in the sugar content in the grape respectively. The requirements regarding minimum alcohol content must of course be observed. Another, but preventive, application is the desugarization of the grape must. The addition of water with grape must or wine (as in Overseas usual) is prohibited in the EU.
The "optimal alcohol content" is determined beforehand by means of appropriate preliminary tests. At this level, also known as the “sweet spot”, the wine achieves the most perfect possible harmony between Aroma. fruitiness and taste, A small batch of the wine with a very high alcohol content is partially dealcoholized. Then a series of wines with gradually different alcohol content is created over up to ten blends in small increments of 0.1 to 0.2% vol. Then these will sensory tasted and the taste "best" wine determined. Then the reduction to this ideal level for the total quantity takes place.
In the research institute Geisenheim a method was developed by means of which enzyme Glucose oxidase is the one present in the grape must glucose in gluconic convert. Gluconic acid can depend on the metabolism yeasts cannot be converted into alcohol. This will be according to the two scientists Herbert Grace Crabetree and Louis Pasteur (1822-1895) also as " Crabtree effect "Or" Pasteur effect ". We also experiment with the selection of ineffective yeasts and thus selectively wine balanced Alcohol content generated.
Complete lists of the numerous vinification measures or cellar techniques, as well as the various types of wine, sparkling wine and distillate regulated by wine law are under the keyword winemaking contain. There is extensive wine law information under the keyword wine law,