Cryo-extraction

This article deals with physical process engineering for material separation. For the form of therapy in ophthalmology, see cryoextraction of the eye lens .

Cryo-extraction is a physical process technology in which substances are separated by means of cold or a liquid , a liquid mixture or a solution is specifically changed in its composition: A proportion of an individual substance freezes completely or partially and can then be physically separated from the starting substance : Separation, separation technology by means of cold.

Production of ice wines

Cryo-extraction takes place when frozen fruit is squeezed. Some of the water remains in the form of ice in the pomace . In viticulture , this method has gained economic importance.

If berries did not ripen properly in normal weather, they were often left hanging for game feed. In January 1830, winemakers harvested grapes from the previous 1829 vintage that had got stuck, accidentally frozen due to night frost. They tried to squeeze these grapes and unexpectedly received a very sugar and acid-rich must that could be fermented into wine . A large part of the water contained in the berries was frozen to ice. The ice crystals remained with the berry skins in the press . If the amount of must was reduced, the result was must with increased sugar and acid content.

Since then this wine has been known as ice wine .

This process is used in winemaking, e.g. B. in problematic years in sweet wine production in Sauternes : grapes are brought into cold stores and frozen at temperatures around −10 ° C, then pressed. In Germany this method of making wine is prohibited.

Production of low-alcohol beer

The process of freeze distillation is technically similar, but it is used after fermentation to modify the alcohol gradation. This process is used in the production of low-alcohol beer .