Term for the crystalline mixture of sparingly soluble salts of tartaric acid, mainly of potassium hydrogen tartrate (including potassium bitartrate) or, to a lesser extent, calcium tartrate obtained by combining tartaric acid with potassium or calcium forms. Prose names are wine diamonds or wine stars. Tartar is particularly common in wines from overripe or late harvested grapes, 90% of these are potassium hydrogen tartrate. It differs in the form of glass fragments of similar small crystals, rods and leaves. This can already be done in the fermentation or expansion tank (raw wine stone), especially in cold treatment. The crystal formation increases with increasing alcohol content, low temperature and rising PH value (from 3.2) too. It can also lead to color changes or calcium clouding.
Tartar is sparingly soluble in water and therefore settles on tank and barrel walls, on the bottom of the bottle or on the cork. In most cases, this is done only in the bottle, which is favored in cool storage. The color is reddish to brown with red wine or whitish to grayish yellow with white wine. He is completely harmless to health, feels like sharp-edged sand and tastes neutral to sour. It is none wine faults but he is undesirable for purely optical or aesthetic reasons. Weinstein has the advantage over the depot (where it may be included) that it can be separated from the wine relatively easily. Due to modern filter and stabilization methods, tartar is hardly found today.
Before the bottling if necessary, tartar stability tests are carried out by determining the saturation temperature. A simple option is the "refrigerator test", in which two sample bottles (one with 2 ml alcohol enrich = mimic low temperature) are kept in the refrigerator for five to seven days and shaken daily. If no crystallization, the wine can be considered as tartar stable. For the purpose of inhibiting the formation of tartar metatartaric before the bottling added. The effectiveness is depending on quality and Weinsteinübersättigung at below 20 ° Celsius 12 to 36 months.
Tartar is precipitated by various methods (removed). These are electrodialysis, Cold stabilization (see beautiful ) or Contact method, A stabilization can also with the newly approved since 2009 Miitel CMC respectively. Fast tartar stabilization is only possible with lower temperatures. Quality-conscious producers, however, a cooling below -4 ° Celsius is avoided in order to protect the wine. In the Middle Ages, tartar and from it were produced Weinstein oil used as a remedy (see Tartarus ). A list of all wine ingredients is under total extract contain.