Sediment in Your Wine Glass
Nearly all sediment found in wine is naturally occurring and is in no way harmful.
In fact, many wine pros and enthusiasts like to see a bit of sediment in their wines, particularly red wines that have been in bottles for more than five years. Sediment in wine can indicate a wine that has not been heavily filtered or otherwise processed.
Sediment is a part of winemaking. At the bottom of every fermenter, you will find a sediment layer comprising dead yeast cells, grape parts, tartrates, pigment polymers, and other disagreed solids.
When wine ages in a cask, many of these same items fall from the wine over time and are separated from the clear wine before bottling.
Once a wine is in the bottle, it may develop fine solids that become sediment over time as the wine ages (even when the wine is perfectly clear at bottling). You will rarely see sediment in wines younger than five years, which is fairly common in red wines aged 10 years or older.
Sediments found in wine bottles include polysaccharides, proteins, pigment, and tartrates (potassium bitartrate crystals). Tartrates, when collected in tank and barrel at the winery, can be collected, sold, and processed into cream of tartar, which is a common kitchen item known to almost any baker.
While sediment in your wine is totally harmless, few people want a mouthful of chunkies while sipping their wine. You can avoid most sediment by carefully decanting the wine and leaving most of the solids in the bottle. See our story on Decanting Wine.