Definition - What does Tartrates mean?
Tartrates are crystals sometimes found at the bottom of a wine bottle or settled at the bottom of a wine glass. They are components of tartaric acid and are a natural occurrence which can form when wines are placed in cooler temperatures. Decanting a wine can prevent these crystals from being poured into a wine glass.
WineFrog explains Tartrates
Tartrates, which some refer to as "small chards of glass", sometimes found on a wine cork or at the bottom of a wine glass, are actually a salt. The salt is an organic compound of tartaric acid.
The crystals are deposits which separate from wine during fermentation and aging. The separation occurs because they are not soluble in alcohol.
They can be found especially in unfiltered wines and may not immediately appear. It is often when the wines are placed in cooler conditions that are not favorable to wine, such as being stored in a refrigerator. This is why some wineries prefer to put their wines through a cold-stabilization process. The process brings down the temperature of a wine, via cooling jackets, allowing for the tartrate crystals to form. After some time, they precipitate to the bottom of the vat. Then the wine can be racked and removed, leaving the tartrates behind.
This process is much more gentle on white wine, since filtering it can remove delicate aromas and flavors.