Definition - What does Sediment mean?
Sediment in wine is the natural and organic compounds of the wine that were either intentionally or unintentionally leftover during the fining, filtering, aging and bottling processes.
There are two types of sediment, tartrates and colloids, which can be present in your glass, and then there's are lees, which is sediment that is present during the winemaking process. Either way sediments are harmless and can sometimes add to the taste, flavors and bouquet of the wine.
WineFrog explains Sediment
The two types of common sediments that are present after the wine is bottled are tartrates and colloids. Tartrate sediments are crystalline formations that come from potassium bitartrate and tartaric acid (both of which naturally occur in wine) combining together in colder conditions. The cold conditions during the aging process in barrels or in bottles in a wine cellar can accelerate the binding of the potassium and acid molecules, which produces sediment.
Colloids are smaller, less noticeable sediments that occur more slowly and usually within wines that have aged in the bottle for many years. Colloids can be present even if the wine was filtered out and to remove them from the glass the use of a decanter is recommended.
Finally, lees are sediments that are usually found in the wine before processing and filtering such as stems, seeds and skins. These solids that are leftover can be removed via the fining process, or in some cases, left in the juice to add more complex flavors and compounds to the wine.