Settling and Racking

After lees has settled to the bottom of a vessel, the clear wine is siphoned or pumped into another barrel or tank. The racking process helps improve clarity while providing a degree of aeration that works to prevent the development of aromas associated with reduction.

As solids precipitate out and settle to the bottom, a discernible layer develops between the solids and clear wine. Racking draws off the wine all the way down to this layer. During racking, care is taken not to agitate the solids as they will re-disperse into the clarified wine liquid if disturbed.

Three instances when excess solids are commonly present are immediately after the grapes are pressed, just following fermentation and after the addition of any fining agents. Settling is most effective at colder temperatures. The coolness inhibits solubility and helps denser materials to fall to the bottom of the container. Settling usually will occur in one or two days for larger solids. Finer particles can require longer periods of time, and may even remain suspended in wine requiring filtration to remove.