Racking (oenology)
The tap (in French: soutirage ) is a basement technical process , in which the cleared wine from the sediment (dead yeast cells , undissolved parts of pulp and grape skin, sediments ) is disconnected. The tapping is usually done by pumping or, more gently, by siphoning into an empty container. In large wineries, tapping tanks are available, the suction nozzles of which are height-adjustable and therefore correctly positioned and optimally positioned above the sediment. This enables the sediment to be removed quickly and completely during racking.
One speaks of the first racking ( coarse yeast ) immediately after the alcoholic fermentation and of the second racking ( fine yeast ) after the first winter cold, after the first tartar has precipitated. In some wineries, further racking takes place after fining steps . More recently, this practice of frequent racking has been abandoned.
In industrial production, the drinks in question are usually filtered or centrifuged with kieselguhr so that one does not have to wait for the natural settling process to take place.
In addition to separating the sediment from the wine, racking also has some useful side effects. With each racking, a small amount of carbon dioxide is released from the young wine . As a result, the wines appear less aggressive and rounder if the amount of bound carbonic acid falls below 300 - 400 mg / L. In addition, the contents of the barrel are homogenized again and a small amount of oxygen is added to the wine.
literature
- Jancis Robinson : The Oxford Wine Lexicon . Hallwag, Gräfe and Unzer, Munich 2006, ISBN 3-8338-0691-5 .
- Émile Peynaud , Jacques Blouin: Connaissance et travail du vin . Dunod, Paris 2005, ISBN 2-10-049296-9 .