Definition: Sediment (in the bottle)

My wine has sediment: what should I do?

Some bottles of wine have a strange deposit, which is often just annoying, but can sometimes be alarming. What exactly is it? Is the wine still safe to drink? This harmless sediment, which consists of tartaric acid, as well as traces of colouring agents and tannins, is generally found in powerful, lightly filtered and fairly aged red wines. Please note that we favour light filtration that is as natural as possible. It has never been possible to filter out only the undesirable elements. All filtration also removes certain qualities from a wine. Depending on the type of wine, it can be very grainy or, on the contrary, very fine. While the coarsest particles settle quickly and remain at the bottom of the bottle when a glass is poured, the finer ones can remain in suspension for a long time and cause the wine to remain cloudy. Wine merchants and sommeliers therefore recommend placing old bottles in an upright position a few days before consumption so that the sediment settles at the bottom. It is then important to pour the wine gently and continuously, shaking the bottle as little as possible when serving several people in succession, i.e. avoiding lifting the neck of the bottle between each glass. This action produces a "water hammer" effect, which immediately stirs up the sediment.

The wine can also be decanted in a single continuous operation, which is easier and more effective in removing sediment. However, this operation requires great care. The angle between the bottle and the decanter should be as obtuse as possible, so that the wine flows smoothly from one to the other. The decanting process must be stopped as soon as the first particles of sediment appear in the neck of the bottle. White wines often have a more granular and crystalline sediment. However, the consistency of the sediment can also be very fine, making the wine more cloudy. These sediments are generally as harmless as those in red wine, but simply unpleasant in the mouth. They are mainly formed as a result of significant temperature variations, which precipitate excess tartaric acid in the form of potassium tartrates (potassium salt of tartaric acid, sometimes called "wine stone" or "gravelle").

This process does not affect the quality of the wine, which remains perfectly safe to drink. This natural deacidification may slightly soften white wines, but does not spoil their taste. However, with the exception of fine wines, most bottles with sediment should be consumed fairly quickly.

It is better for the winemaker to lower the temperature of the wine in vats significantly before bottling so that the tartar precipitation forms in the vat rather than in the bottle!

Partial source: COOP wines