Wine sediment is also known as crystals or tartrates. Sediment forms in wine that is stored for several years, especially full-bodied red wines that are stored in cold locations during the winter.
Sediment mostly occurs when tannin molecules in the wine grow larger and sink to the bottom of the bottle. The sediment that forms in white wine is made up of tartrate crystals, which are the same crystals used in cream of tartar. Sediment can be filtered out by slowly pouring the wine from its existing bottle into a decanter, being careful to leave the crystals and the last bit of wine in the bottle.