Why do some wines have sediment and are there different kinds of sediment in wine? Sediment can form naturally in wine both during the fermentation process and while maturing in the bottle. Some wines are more likely to develop sediment and some wines will almost never form sediment. Wine sediment isn't harmful and can be seen as as a sign of wine's quality. You may want to separate sediment from wine with a decanter before serving and drinking.

Sediment Caused During Wine Production

The initial sediment which forms in wine appears during the fermentation process and is called lees. The lees sediment consists of dead yeast cells, proteins, stems, bits of skin, and other solid matter that has settled to the bottom of the fermentation tanks. Wine is left with the lees for a while so it can develop more character and complexity. If the mixture is handled incorrectly some bad flavors can develop. The initial lees sediment is separated from the wine during a process called clarification. This is when the wine is filtered during the transfer from fermentation tanks to aging casks or tanks. In the aging casks more lees sediment can form, so it's not only common for wine to be siphoned out of this first aging cask and into a second one to separate it from the second lees sediment. This process might happen two or three times depending on the wine. Siphoning and clarification can occur quickly or very slowly depending on what the wine maker is trying to achieve. The more a wine is left in contact with the lees sediment at each stage, the more character and complexity it will have. Today you won't find lees sediments in any bottles of wine except among sparkling wines and champagnes made according to traditional methods where secondary fermentation occurs in the bottle itself.

Sediment In The Wine Bottle

When you think about sediment in wine you probably think about the formation of sediment in wine bottles that you have to remove before serving. This kind of sediment only forms in red wines that have been aging for at least eight to ten years or more. A bottle of wine that you bought a couple of months ago, even if it's a red wine, won't have this kind of sediment. The sediment that develops in red wine bottles is formed from tannins and other solid matter that gradually falls to the bottom or side of the bottle. The presence of this material helps give the wine character and complexity, but you don't want to leave it in the wine when you serve it. This kind of sediment can give a bitter flavor to the wine. Even if the sediment is very mild, it will interfere with any of the subtle qualities that have developed during the aging process plus it's not pleasant to look down at red or dark bits in your wine glass. If you're serving a red wine that's been aging for several years, you'll should hold it up to the light to see if a sediment has formed. If it has developed, set the wine bottle upright for a few days before serving so all the sediment collects in small area at the bottom of the bottle. When you open the bottle, decant it first before serving and possibly aerate the wine as well.

Crystalline Sediment

If you find tiny crystals in your wine glass they are not likely to taste bad. They are sometimes treated as a sign of a better wine. The crystal sediment is called tartrate and forms from tartaric acid in grapes. Not all fruit has tartaric acid and its presence in grapes is what allows us to make better wines from grapes than can we can from any other fruit. Because tartaric acid doesn't remain dissolved in alcohol as easily as it does in grape juice, it binds to potassium after fermentation and forms potassium acid tartrates, the crystalline solids that creat the sediment in your wine glass. Because red wines have probably been exposed to cold temperatures less than white wines, they are more likely form tartrate crystals. All wines should probably form tartrate sediment, but modern wine production has introduced cold stabilization and fine filtration which remove most all tartrates. More expensive wines that have been created according to more traditional methods are more likely to produce tartrate sediment. People who prefer the traditional methods of wine production, which includes a lot of wine drinkers in France and Italy, will treat the presence of tartrate sediment as a sign of quality. The tartrate sediment in your wine glass or wine bottle won't hurt you if you drink it and it isn't going to ruin the flavor of your wine, so you don't need to worry about separating the crystals from your wine.