Term (also fine) for various processes to "beautify", "improve", "purify" or "preserve" a young wine. The term " degumming " or " clarifying ", on the other hand, usually refers to the processes used for grape must. In the past, fining mainly meant the clarification of lees in a wine after fermentation, which was also called aerial fining. Today, the term encompasses many different technical cellar measures. Some overlap with preservation methods, which are primarily intended to increase the shelf life and prevent spoilage.
In fining, by adding suitable substances to the freshly fermented wine, unwanted suspended substances are bound by chemical reactions and/or adsorption, which can have negative effects with regard to colour and taste. These are electrically charged. Either negatively like yeasts and tannins or positively like proteins and gelatine. The fining agents must be oppositely charged in order to bind the lees particles to themselves. They are added in dissolved form and form insoluble flakes with the unwanted wine constituents, which sink to the bottom.
History
In ancient times, the Romans were already aware of the effect of whipped egg whites in winemaking. In the Middle Ages, there were some questionable procedures (or wine adulterations); for example, a "colour and taste improvement" with cattle blood. In the famous classic "Von Baw, Pfleg und Brauch des Weins" by the clergyman Johann Rasch (1540-1612), who worked in Vienna, some techniques are described in detail. Among other things, he explains how to restore a cloudy wine, namely by adding freshly milked milk that is still warm from the cow. It was also known that certain substances such as isinglass, gelatine, Spanish earth (kaolin clay) and coal bind the suspended particles in the wine.
Mode of action
Fining ultimately achieves several effects. First of all, the natural settling of lees is accelerated considerably. Furthermore, substances bound in the wine are removed, which can lead to turbidity or negative effects after bottling. In addition, the removal of filtration-inhibiting substances facilitates any subsequent filtration. Finally, wine defects are at best prevented in the first place or eliminated after they occur. A distinction can be made between the three groups of physical-chemical substances such as proteins, tannins, crystals (tartar) and heavy metals, biological substances such as yeasts and...
